diff --git a/documentation/content/en/books/handbook/config/_index.adoc b/documentation/content/en/books/handbook/config/_index.adoc index c9ce62d599..e67ee10a3d 100644 --- a/documentation/content/en/books/handbook/config/_index.adoc +++ b/documentation/content/en/books/handbook/config/_index.adoc @@ -1,1589 +1,1586 @@ --- title: Chapter 14. Configuration, Services, Logging and Power Management part: Part III. System Administration prev: books/handbook/partiii next: books/handbook/boot description: This chapter explains much of the FreeBSD configuration files, how to enable or disable a service, how to configure the logging system and the power management area. tags: ["configuration", "services", "cron", "periodic", "logging", "configuration files", "sysctl", "swap", "power management"] showBookMenu: true weight: 18 path: "/books/handbook/" --- [[config-tuning]] = Configuration, Services, Logging and Power Management :doctype: book :toc: macro :toclevels: 1 :icons: font :sectnums: :sectnumlevels: 6 :sectnumoffset: 14 :partnums: :source-highlighter: rouge :experimental: :images-path: books/handbook/config/ ifdef::env-beastie[] ifdef::backend-html5[] :imagesdir: ../../../../images/{images-path} endif::[] ifndef::book[] include::shared/authors.adoc[] include::shared/mirrors.adoc[] include::shared/releases.adoc[] include::shared/attributes/attributes-{{% lang %}}.adoc[] include::shared/{{% lang %}}/teams.adoc[] include::shared/{{% lang %}}/mailing-lists.adoc[] include::shared/{{% lang %}}/urls.adoc[] toc::[] endif::[] ifdef::backend-pdf,backend-epub3[] include::../../../../../shared/asciidoctor.adoc[] endif::[] endif::[] ifndef::env-beastie[] toc::[] include::../../../../../shared/asciidoctor.adoc[] endif::[] [[config-synopsis]] == Synopsis One of the important aspects of FreeBSD is proper system configuration. This chapter explains much of the FreeBSD configuration process, including some of the parameters which can be set to tune a FreeBSD system. Before reading this chapter, you should: * Understand UNIX(R) and FreeBSD basics (crossref:basics[basics,FreeBSD Basics]). After reading this chapter, you will know: * How to use the various configuration files in [.filename]#/etc#. * The basics of [.filename]#rc.conf# configuration and [.filename]#/usr/local/etc/rc.d# startup scripts. * How to tune FreeBSD using man:sysctl[8] variables. * How to configure the power management in FreeBSD. [[configtuning-configfiles]] == Configuration Files FreeBSD maintains a clear separation between the base system and third party applications and therefore this affects where the configuration files of these applications are located. FreeBSD base system configuration is located at the [.filename]#/etc# directory, and the [.filename]#/usr/local/etc# directory contains all the configuration files of the applications installed on the system through the ports collection and packages. The kernel state configuration is located in [.filename]#/etc/sysctl.conf#. In the section <>, the operation of man:sysctl[8] will be explained in more detail. For more information about the FreeBSD file system structure refer to man:hier[7]. As a general rule, configuration files do not use a standard on what syntax they must follow. Although it is true that the `#` character is normally used to comment a line and that each line has a configuration variable. [NOTE] ==== Some applications like man:pkg[8] are starting to use the link:https://github.com/vstakhov/libucl[Universal Configuration Language (UCL)]. ==== === The [.filename]#/etc# directory The [.filename]#/etc# directory contains all of the FreeBSD base system configuration files that are responsible for configuring FreeBSD. [CAUTION] ==== *Extreme* caution must be taken when modifying files in the [.filename]#/etc# directory; misconfiguration could make FreeBSD unbootable or malfunction. ==== [.informaltable] [cols="1,1", frame="none"] |=== |[.filename]#/etc# |System configuration files and scripts. |[.filename]#/etc/defaults# |Default system configuration files, see man:rc[8] for more information. |[.filename]#/etc/fstab# |man:fstab[5] contains descriptive information about the various file systems. |[.filename]#/etc/mail# |Extra man:sendmail[8] configuration and other MTA configuration files. |[.filename]#/etc/mtree# |mtree configuration files, see man: mtree[8] for more information. |[.filename]#/etc/pam.d# |Configuration files for the Pluggable Authentication Modules (PAM) library. |[.filename]#/etc/periodic# |Scripts that are run daily, weekly, and monthly, via man:cron[8], see man:periodic[8] for more information. |[.filename]#/etc/rc.d# |System and daemon startup/control scripts, see man:rc[8] for more information. |[.filename]#/etc/rc.conf# |Contains descriptive information about the local host name, configuration details for any potential network interfaces and which services should be started up at system initial boot time. More information in <> |[.filename]#/etc/security# |OpenBSM audit configuration files, see man:audit[8] for more information. |[.filename]#/etc/ppp# |ppp configuration files, see man:ppp[8] for more information. |[.filename]#/etc/ssh# |OpenSSH configuration files, see man:ssh[1] for more information. |[.filename]#/etc/ssl# |OpenSSL configuration files. |[.filename]#/etc/sysctl.conf# |Contains settings for the kernel. More information in <> |=== [[configtuning-sysctl]] === The sysctl utility The man:sysctl[8] utility is used to make changes to a running FreeBSD system. The man:sysctl[8] utility retrieves kernel state and allows processes with appropriate privilege to set kernel state. The state to be retrieved or set is described using a "Management Information Base" ("MIB") style name, described as a dotted set of components. .Management Information Base [.informaltable] [cols="1,1", frame="none"] |=== |sysctl |"Magic" numbers |kern |Kernel functions and features |vm |virtual memory |vfs |Filesystem |net |Network |debug |Debugging parameters |hw |Hardware |machdep |Machine dependent |user |Userland |p1003_1b |POSIX 1003.1B |=== At its core, man:sysctl[8] serves two functions: to read and to modify system settings. To view all readable variables: [source,shell] .... % sysctl -a .... The output should be similar to the following: [.programlisting] .... kern.ostype: FreeBSD ... vm.swap_enabled: 1 vm.overcommit: 0 vm.domain.0.pidctrl.kdd: 8 vm.domain.0.pidctrl.kid: 4 vm.domain.0.pidctrl.kpd: 3 ... vfs.zfs.sync_pass_rewrite: 2 vfs.zfs.sync_pass_dont_compress: 8 vfs.zfs.sync_pass_deferred_free: 2 .... To read a particular variable, specify its name: [source,shell] .... % sysctl kern.maxproc .... The output should be similar to the following: [.programlisting] .... kern.maxproc: 1044 .... The Management Information Base (MIB) is hierarchical and hence, specifying a prefix prints all the nodes hanging from it: [source,shell] .... % sysctl net .... The output should be similar to the following: [.programlisting] .... net.local.stream.recvspace: 8192 net.local.stream.sendspace: 8192 net.local.dgram.recvspace: 16384 net.local.dgram.maxdgram: 2048 net.local.seqpacket.recvspace: 8192 net.local.seqpacket.maxseqpacket: 8192 net.local.sockcount: 60 net.local.taskcount: 25 net.local.recycled: 0 net.local.deferred: 0 net.local.inflight: 0 net.inet.ip.portrange.randomtime: 1 net.inet.ip.portrange.randomcps: 9999 [...] .... To set a particular variable, use the _variable_=_value_ syntax: [source,shell] .... # sysctl kern.maxfiles=5000 .... The output should be similar to the following: [.programlisting] .... kern.maxfiles: 2088 -> 5000 .... [NOTE] ==== To keep the configuration after a reboot it is necessary to add these variables to the [.filename]#/etc/sysctl.conf# file as explained below. ==== [[configtuning-sysctlconf]] === The [.filename]#/etc/sysctl.conf# file The configuration file for man:sysctl[8], [.filename]#/etc/sysctl.conf#, looks much like [.filename]#/etc/rc.conf#. Values are set using a `variable=value` syntax. [NOTE] ==== The specified values are set after the system goes into multi-user mode. Not all variables are settable in this mode. ==== For example, to turn off logging of fatal signal exits and prevent users from seeing processes started by other users, the following tunables can be set in [.filename]#/etc/sysctl.conf#: [.programlisting] .... # Do not log fatal signal exits (e.g., sig 11) kern.logsigexit=0 # Prevent users from seeing information about processes that # are being run under another UID. security.bsd.see_other_uids=0 .... To obtain more information about what function a particular sysctl has, the following command can be executed: [source,shell] .... % sysctl -d kern.dfldsiz .... The output should be similar to the following: [.programlisting] .... kern.dfldsiz: Initial data size limit .... [[configtuning-core-configuration]] === Managing System-Specific Configuration The principal location for system configuration information is [.filename]#/etc/rc.conf#. This file contains a wide range of configuration information and it is read at system startup to configure the system. It provides the configuration information for the [.filename]#rc*# files. The entries in [.filename]#/etc/rc.conf# override the default settings in [.filename]#/etc/defaults/rc.conf#. [TIP] ==== The file [.filename]#/etc/defaults/rc.conf# containing the default settings should not be edited. Instead, all system-specific changes should be made to [.filename]#/etc/rc.conf#. ==== A number of strategies may be applied in clustered applications to separate site-wide configuration from system-specific configuration in order to reduce administration overhead. The recommended approach is to place system-specific configuration into [.filename]#/etc/rc.conf.local#. For example, these entries in [.filename]#/etc/rc.conf# apply to all systems: [.programlisting] .... sshd_enable="YES" keyrate="fast" defaultrouter="10.1.1.254" .... Whereas these entries in [.filename]#/etc/rc.conf.local# apply to this system only: [.programlisting] .... hostname="node1.example.org" ifconfig_fxp0="inet 10.1.1.1/8" .... Distribute [.filename]#/etc/rc.conf# to every system using an application such as rsync or puppet, while [.filename]#/etc/rc.conf.local# remains unique. Upgrading the system will not overwrite [.filename]#/etc/rc.conf#, so system configuration information will not be lost. [TIP] ==== Both [.filename]#/etc/rc.conf# and [.filename]#/etc/rc.conf.local# are parsed by man:sh[1]. This allows system operators to create complex configuration scenarios. Refer to man:rc.conf[5] for further information on this topic. ==== [[configtuning-rcd]] == Managing Services in FreeBSD FreeBSD uses the man:rc[8] system of startup scripts during system initialization and for managing services. The scripts listed in [.filename]#/etc/rc.d# provide basic services which can be controlled with the `start`, `stop`, and `restart` options to man:service[8]. A basic script may look similar to the following: [.programlisting] .... #!/bin/sh # # PROVIDE: utility # REQUIRE: DAEMON # KEYWORD: shutdown . /etc/rc.subr name=utility rcvar=utility_enable command="/usr/local/sbin/utility" load_rc_config $name # # DO NOT CHANGE THESE DEFAULT VALUES HERE # SET THEM IN THE /etc/rc.conf FILE # utility_enable=${utility_enable-"NO"} pidfile=${utility_pidfile-"/var/run/utility.pid"} run_rc_command "$1" .... Refer to extref:{rc-scripting}[this article] for instructions on how to create custom man:rc[8] scripts. [[configtuning-starting-services]] === Starting Services Many users install third party software on FreeBSD from the Ports Collection and require the installed services to be started upon system initialization. Services, such as package:security/openssh-portable[] or package:www/nginx[] are just two of the many software packages which may be started during system initialization. This section explains the procedures available for starting services. Since the man:rc[8] system is primarily intended to start and stop services at system startup and shutdown time, the `start`, `stop` and `restart` options will only perform their action if the appropriate [.filename]#/etc/rc.conf# variable is set. So the first step to start a service, like for example package:www/nginx[] is to add it to [.filename]#/etc/rc.conf# by executing the following command: [source,shell] .... # sysrc nginx_enable="YES" .... Then nginx can be started executing the following command: [source,shell] .... # service nginx start .... [TIP] ==== To `start`, `stop` or `restart` a service regardless of the settings in [.filename]#/etc/rc.conf#, these commands should be prefixed with "one". For instance, to start package:www/nginx[] regardless of the current [.filename]#/etc/rc.conf# setting, execute the following command: [source,shell] .... # service nginx onestart .... ==== [[configtuning-status-services]] === Status of a Service To determine if a service is running, use the `status` subcommand. For example, to verify that package:www/nginx[] is running: [source,shell] .... # service nginx status .... The output should be similar to the following: [.programlisting] .... nginx is running as pid 27871. .... [[configtuning-reload-services]] === Reload a Service In some cases, it is also possible to `reload` a service. This attempts to send a signal to an individual service, forcing the service to reload its configuration files. In most cases, this means sending the service a `SIGHUP` signal. *Not all services support this feature.* The man:rc[8] system is used for network services and it also contributes to most of the system initialization. For instance, when the [.filename]#/etc/rc.d/bgfsck# script is executed, it prints out the following message: [source,shell] .... Starting background file system checks in 60 seconds. .... This script is used for background file system checks, which occur only during system initialization. Many system services depend on other services to function properly. For example, man:yp[8] and other RPC-based services may fail to start until after the man:rpcbind[8] service has started. Additional information can be found in man:rc[8] and man:rc.subr[8]. === Using Services to Start Services Other services can be started using man:inetd[8]. Working with man:inetd[8] and its configuration is described in depth in crossref:network-servers[network-inetd,“The inetd Super-Server”]. In some cases, it may make more sense to use man:cron[8] to start system services. This approach has a number of advantages as man:cron[8] runs these processes as the owner of the man:crontab[5]. This allows regular users to start and maintain their own applications. The `@reboot` feature of man:cron[8], may be used in place of the time specification. This causes the job to run when man:cron[8] is started, normally during system initialization. [[cron-periodic]] == Cron and Periodic Scheduling tasks to run at a certain day or time is a very common task on FreeBSD. The tool in charge of performing this task is man:cron[8]. In addition to tasks that can be scheduled by the user via man:cron[8], FreeBSD performs routine background tasks managed by man:periodic[8]. [[configtuning-cron]] === Cron The man:cron[8] utility runs in the background and regularly checks [.filename]#/etc/crontab# for tasks to execute and searches [.filename]#/var/cron/tabs# for custom crontab files. These files are used to schedule tasks which cron runs at the specified times. Each entry in a crontab defines a task to run and is known as a _cron job_. Two different types of configuration files are used: the system crontab, which should not be modified, and user crontabs, which can be created and edited as needed. The format used by these files is documented in man:crontab[5]. The format of the system crontab, [.filename]#/etc/crontab# includes a `who` column which does not exist in user crontabs. In the system crontab, cron runs the command as the user specified in this column. In a user crontab, all commands run as the user who created the crontab. User crontabs allow individual users to schedule their own tasks. The `root` user can also have a user [.filename]#crontab# which can be used to schedule tasks that do not exist in the system [.filename]#crontab#. Here is a sample entry from the system crontab, [.filename]#/etc/crontab#: [.programlisting] .... # /etc/crontab - root's crontab for FreeBSD # -# $FreeBSD$ <.> +# <.> # SHELL=/bin/sh PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin <.> # #minute hour mday month wday who command <.> # # Save some entropy so that /dev/random can re-seed on boot. */11 * * * * operator /usr/libexec/save-entropy <.> # # Rotate log files every hour, if necessary. 0 * * * * root newsyslog # # Perform daily/weekly/monthly maintenance. 1 3 * * * root periodic daily 15 4 * * 6 root periodic weekly 30 5 1 * * root periodic monthly # # Adjust the time zone if the CMOS clock keeps local time, as opposed to # UTC time. See adjkerntz(8) for details. 1,31 0-5 * * * root adjkerntz -a .... <.> Lines that begin with the `+#+` character are comments. A comment can be placed in the file as a reminder of what and why a desired action is performed. Comments cannot be on the same line as a command or else they will be interpreted as part of the command; they must be on a new line. Blank lines are ignored. <.> The equals (`=`) character is used to define any environment settings. In this example, it is used to define the `SHELL` and `PATH`. If the `SHELL` is omitted, cron will use the default Bourne shell. If the `PATH` is omitted, the full path must be given to the command or script to run. <.> This line defines the seven fields used in a system crontab: `minute`, `hour`, `mday`, `month`, `wday`, `who`, and `command`. The `minute` field is the time in minutes when the specified command will be run, the `hour` is the hour when the specified command will be run, the `mday` is the day of the month, `month` is the month, and `wday` is the day of the week. These fields must be numeric values, representing the twenty-four hour clock, or a `*`, representing all values for that field. The `who` field only exists in the system crontab and specifies which user the command should be run as. The last field is the command to be executed. <.> This entry defines the values for this cron job. The `\*/11`, followed by several more `*` characters, specifies that `/usr/libexec/save-entropy` is invoked by `operator` every eleven minutes of every hour, of every day and day of the week, of every month. Commands can include any number of switches. However, commands which extend to multiple lines need to be broken with the backslash "\" continuation character. [[configtuning-installcrontab]] === Creating a User Crontab To create a user crontab, invoke `crontab` in editor mode: [source,shell] .... % crontab -e .... This will open the user's crontab using the default text editor. The first time a user runs this command, it will open an empty file. Once a user creates a crontab, this command will open that file for editing. It is useful to add these lines to the top of the crontab file in order to set the environment variables and to remember the meanings of the fields in the crontab: [.programlisting] .... SHELL=/bin/sh PATH=/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin # Order of crontab fields # minute hour mday month wday command .... Then add a line for each command or script to run, specifying the time to run the command. This example runs the specified custom Bourne shell script every day at two in the afternoon. Since the path to the script is not specified in `PATH`, the full path to the script is given: [.programlisting] .... 0 14 * * * /home/user/bin/mycustomscript.sh .... [TIP] ==== Before using a custom script, make sure it is executable and test it with the limited set of environment variables set by cron. To replicate the environment that would be used to run the above cron entry, use: [.programlisting] .... env -i SHELL=/bin/sh PATH=/etc:/bin:/sbin:/usr/bin:/usr/sbin HOME=/home/user LOGNAME=user /home/user/bin/mycustomscript.sh .... The environment set by cron is discussed in man:crontab[5]. Checking that scripts operate correctly in a cron environment is especially important if they include any commands that delete files using wildcards. ==== When finished editing the crontab, save the file. It will automatically be installed, and cron will read the crontab and run its cron jobs at their specified times. To list the cron jobs in a crontab, use this command: [source,shell] .... % crontab -l .... The output should be similar to the following: [.programlisting] .... 0 14 * * * /home/user/bin/mycustomscript.sh .... To remove all of the cron jobs in a user crontab: [source,shell] .... % crontab -r .... The output should be similar to the following: [.programlisting] .... remove crontab for user? y .... [[configtuning-periodic]] === Periodic FreeBSD provides a set of system management scripts to check status of various subsystems, perform security-related checks, rotate log files, etc. These scripts are run on a periodic basis: daily. weekly, or monthly. The management of these tasks is performed by man:periodic[8] and its configuration resides in man:periodic.conf[5]. The periodic tasks are initiated by entries in the system crontab, shown above. Scripts executed by man:periodic[8] are located in [.filename]#/etc/periodic/# for base utilities and in [.filename]#/usr/local/etc/periodic/# for third-party software. They are organized in 4 subdirectories, daily, weekly, monthly and security. [[enable-disable-periodic]] === Enable or Disable Periodic Tasks FreeBSD has some scripts enabled by default to run periodically. To enable or disable a task, the first step is to edit [.filename]#/etc/periodic.conf# executing the following command: [source,shell] .... # ee /etc/periodic.conf .... And then to enable, for example, `daily_status_zfs_enable` put the following content in the file: [.programlisting] .... daily_status_zfs_enable="YES" .... To disable a task that is active by default, all that needs to be done is to change `YES` to `NO`. [[configuring-output-periodic-tasks]] === Configuring the Output of Periodic Tasks In [.filename]#/etc/periodic.conf# the variables `daily_output`, `weekly_output` and `monthly_output` specifies where to send the results of the script execution. By default the output of the periodic scripts are emailed to root, and therefore it is best to read root's mail or alias root to a mailbox that is monitored. To send the results to another email or to other emails, add the email addresses separated by spaces to [.filename]#/etc/periodic.conf#: [.programlisting] .... daily_output="email1@example.com email2@example.com" weekly_output="email1@example.com email2@example.com" monthly_output="email1@example.com email2@example.com" .... To log periodic output instead of receiving it as email, add the following lines to [.filename]#/etc/periodic.conf#. man:newsyslog[8] will rotate these files at the appropriate times: [.programlisting] .... daily_output=/var/log/daily.log weekly_output=/var/log/weekly.log monthly_output=/var/log/monthly.log .... [[configtuning-syslog]] == Configuring System Logging Generating and reading system logs is an important aspect of system administration. The information in system logs can be used to detect hardware and software issues as well as application and system configuration errors. This information also plays an important role in security auditing and incident response. Most system daemons and applications will generate log entries. FreeBSD provides a system logger, man:syslogd[8], to manage logging. By default, syslogd is enabled and started when the system boots. This section describes how to configure the FreeBSD system logger for both local and remote logging and how to perform log rotation and log management. === Configuring Local Logging The configuration file, [.filename]#/etc/syslog.conf#, controls what syslogd does with log entries as they are received. There are several parameters to control the handling of incoming events. The _facility_ describes which subsystem generated the message, such as the kernel or a daemon, and the _level_ describes the severity of the event that occurred. This makes it possible to configure if and where a log message is logged, depending on the facility and level. It is also possible to take action depending on the application that sent the message, and in the case of remote logging, the hostname of the machine generating the logging event. This configuration file contains one line per action, where the syntax for each line is a selector field followed by an action field. The syntax of the selector field is _facility.level_ which will match log messages from _facility_ at level _level_ or higher. It is also possible to add an optional comparison flag before the level to specify more precisely what is logged. Multiple selector fields can be used for the same action, and are separated with a semicolon (`;`). Using `*` will match everything. The action field denotes where to send the log message, such as to a file or remote log host. As an example, here is the default [.filename]#/etc/syslog.conf# from FreeBSD: [.programlisting] .... -# $FreeBSD$ -# # Spaces ARE valid field separators in this file. However, # other *nix-like systems still insist on using tabs as field # separators. If you are sharing this file between systems, you # may want to use only tabs as field separators here. # Consult the syslog.conf(5) manpage. *.err;kern.warning;auth.notice;mail.crit /dev/console <.> *.notice;authpriv.none;kern.debug;lpr.info;mail.crit;news.err /var/log/messages security.* /var/log/security auth.info;authpriv.info /var/log/auth.log mail.info /var/log/maillog <.> cron.* /var/log/cron !-devd *.=debug /var/log/debug.log <.> *.emerg * daemon.info /var/log/daemon.log # uncomment this to log all writes to /dev/console to /var/log/console.log # touch /var/log/console.log and chmod it to mode 600 before it will work #console.info /var/log/console.log # uncomment this to enable logging of all log messages to /var/log/all.log # touch /var/log/all.log and chmod it to mode 600 before it will work #*.* /var/log/all.log # uncomment this to enable logging to a remote loghost named loghost #*.* @loghost # uncomment these if you're running inn # news.crit /var/log/news/news.crit # news.err /var/log/news/news.err # news.notice /var/log/news/news.notice # Uncomment this if you wish to see messages produced by devd # !devd # *.>=notice /var/log/devd.log <.> !* include /etc/syslog.d include /usr/local/etc/syslog.d .... <.> Matches all messages with a level of `err` or higher, as well as `kern.warning`, `auth.notice` and `mail.crit`, and sends these log messages to the console ([.filename]#/dev/console#). <.> Matches all messages from the `mail` facility at level `info` or above and logs the messages to [.filename]#/var/log/maillog#. <.> Uses a comparison flag (`=`) to only match messages at level `debug` and logs them to [.filename]#/var/log/debug.log#. <.> Is an example usage of a program specification. This makes the rules following it only valid for the specified program. In this case, only the messages generated by man:devd[8] are logged to [.filename]#/var/log/devd.log#. For more information about [.filename]#/etc/syslog.conf#, its syntax, and more advanced usage examples, see man:syslog.conf[5]. [[logging-facilities]] === Logging Facilities A facility describes the part of the system generating the message. Facilities are a way of separating the different messages so that it is easier for the user to consult the logs. .syslog facilities [options="header", cols="1,1"] |=== | Name | Description | auth | The authorization system: man:login[1], man:su[1], man:getty[8], etc. | authpriv | The same as auth, but logged to a file readable only by root. | console | Messages written to [.filename]#/dev/console# by the kernel console output driver. | cron | Messages written by the man:cron[8] daemon. | daemon | System daemons, such as man:routed[8], that are not provided for explicitly by other facilities. | ftp | The file transfer protocol daemons: man:ftpd[8], man:tftpd[8]. | kern | Messages generated by the kernel. These cannot be generated by any user processes. | lpr | The line printer spooling system: man:lpr[1], man:lpc[8], man:lpd[8], etc. | mail | The mail system. | mark | This facility adds a record every 20 minutes. | news | The network news system. | ntp | The network time protocol system. | security | Security subsystems, such as man:ipfw[4]. | syslog | Messages generated internally by syslogd(8). | user | Messages generated by random user processes. *This is the default facility identifier if none is specified*. | uucp | The Unix-to-Unix Copy system. An ancient protocol. Really weird to see messages from this facility. | local0 through local7 | Reserved for local use. |=== [[logging-levels]] === Logging Levels The level describes the severity of the message, and is a keyword from the following ordered list (higher to lower): .syslog levels [options="header", cols="1,1"] |=== | Name | Description | emerg | A panic condition. This is normally broadcast to all users. | alert | A condition that should be corrected immediately, such as a corrupted system database. | crit | Critical conditions, e.g., hard device errors. | err | Errors. | warning | Warning messages. | notice | Conditions that are not error conditions, but should possibly be handled specially. | info | Informational messages. | debug | Messages that contain information normally of use only when debugging a program. | none | This special level disables a particular facility. |=== [[read-log-messages]] === Read Log Messages By default FreeBSD log files use the format link:https://datatracker.ietf.org/doc/html/rfc3164[rfc3164], also known as The BSD syslog Protocol. Learn more about other formats and how to use them at man:syslog[8]. Typically the logs have the following syntax: [.programlisting] .... date time hostname program[pid]: the message .... The output of the [.filename]#/var/log/cron# file will be used as an example: [.programlisting] .... [...] Jul 16 12:40:00 FreeBSD /usr/sbin/cron[81519]: (root) CMD (/usr/libexec/atrun) Jul 16 12:44:00 FreeBSD /usr/sbin/cron[83072]: (operator) CMD (/usr/libexec/save-entropy) [...] .... Verbose logging, so the facility and the level on each message will be added, can be enabled in man:syslog[8] by running the following command: [source,shell] .... # sysrc syslogd_flags="-vv" .... Once the function is activated, the facility and the level will be displayed in the log as shown in the following example: [.programlisting] .... [...] Jul 16 17:40:00 FreeBSD /usr/sbin/cron[1016]: (root) CMD (/usr/libexec/atrun) Jul 16 17:44:00 FreeBSD /usr/sbin/cron[1030]: (operator) CMD (/usr/libexec/save-entropy) [...] .... === Log Management and Rotation Log files can grow quickly, taking up disk space and making it more difficult to locate useful information. In FreeBSD, man:newsyslog[8] is used to manage log files and attempt to mitigate this. This built-in program periodically rotates and compresses log files, and optionally creates missing log files and signals programs when log files are moved. [NOTE] ==== Since newsyslog is run from man:cron[8], it cannot rotate files more often than it is scheduled to run from man:cron[8]. In the default configuration, it runs every hour. ==== Here is the default configuration in FreeBSD, more information in man:newsyslog.conf[5]: [.programlisting] .... # configuration file for newsyslog -# $FreeBSD$ # # Entries which do not specify the '/pid_file' field will cause the # syslogd process to be signalled when that log file is rotated. This # action is only appropriate for log files which are written to by the # syslogd process (ie, files listed in /etc/syslog.conf). If there # is no process which needs to be signalled when a given log file is # rotated, then the entry for that file should include the 'N' flag. # # Note: some sites will want to select more restrictive protections than the # defaults. In particular, it may be desirable to switch many of the 644 # entries to 640 or 600. For example, some sites will consider the # contents of maillog, messages, and lpd-errs to be confidential. In the # future, these defaults may change to more conservative ones. # # logfilename [owner:group] mode count size when flags [/pid_file] [sig_num] /var/log/all.log 600 7 * @T00 J /var/log/auth.log 600 7 1000 @0101T JC /var/log/console.log 600 5 1000 * J /var/log/cron 600 3 1000 * JC /var/log/daily.log 640 7 * @T00 JN /var/log/debug.log 600 7 1000 * JC /var/log/init.log 644 3 1000 * J /var/log/kerberos.log 600 7 1000 * J /var/log/maillog 640 7 * @T00 JC /var/log/messages 644 5 1000 @0101T JC /var/log/monthly.log 640 12 * $M1D0 JN /var/log/devd.log 644 3 1000 * JC /var/log/security 600 10 1000 * JC /var/log/utx.log 644 3 * @01T05 B /var/log/weekly.log 640 5 * $W6D0 JN /var/log/daemon.log 644 5 1000 @0101T JC /etc/newsyslog.conf.d/[!.]*.conf /usr/local/etc/newsyslog.conf.d/[!.]*.conf .... . `logfilename` - Name of the system log file to be archived. . `[owner:group]` - This optional field specifies the owner and group for the archive file. . `mode` - Specify the file mode of the log file and archives. Valid mode bits are 0666. (That is, read and write permissions for the rotated log may be specified for the owner, group, and others.) . `count` - Specify the maximum number of archive files which may exist. . `size` - When the size of the log file reaches size in kilobytes, the log file will be trimmed as described above. If this field contains an asterisk ('*'), the log file will not be trimmed based on size. . `when` - Consist of an interval, a specific time, or both. Supported options in man:newsyslog.conf[5]. . `flags` - Indicates the flags that newsyslog accepts, supported options in man:newsyslog.conf[5]. . `[/pid_file]` - This optional field specifies the file name containing a daemon's process ID or to find a group process ID. . `[sig_num]` - This optional field specifies the signal that will be sent to the daemon process. [NOTE] ==== The last two fields are optional and specify the name of the Process ID (PID) file of a process and a signal number to send to that process when the file is rotated. ==== [[network-syslogd]] === Configuring Remote Logging Monitoring the log files of multiple hosts can become unwieldy as the number of systems increases. Configuring centralized logging can reduce some of the administrative burden of log file administration. In FreeBSD, centralized log file aggregation, merging, and rotation can be configured using syslogd and newsyslog. This section demonstrates an example configuration, where host `A`, named `logserv.example.com`, will collect logging information for the local network. Host `B`, named `logclient.example.com`, will be configured to pass logging information to the logging server. ==== Log Server Configuration A log server is a system that has been configured to accept logging information from other hosts. Before configuring a log server, check the following: * If there is a firewall between the logging server and any logging clients, ensure that the firewall ruleset allows UDP port 514 for both the clients and the server. * The logging server and all client machines must have forward and reverse entries in the local DNS. If the network does not have a DNS server, create entries in each system's [.filename]#/etc/hosts#. Proper name resolution is required so that log entries are not rejected by the logging server. On the log server, edit [.filename]#/etc/syslog.conf# to specify the name of the client to receive log entries from, the logging facility to be used, and the name of the log to store the host's log entries. This example adds the hostname of `B`, logs all facilities, and stores the log entries in [.filename]#/var/log/logclient.log#. .Sample Log Server Configuration [example] ==== [.programlisting] .... +logclient.example.com *.* /var/log/logclient.log .... ==== When adding multiple log clients, add a similar two-line entry for each client. More information about the available facilities may be found in man:syslog.conf[5]. Next, execute the following commands: [source,shell] .... # sysrc syslogd_enable="YES" # sysrc syslogd_flags="-a logclient.example.com -v -v" .... The first entry starts syslogd at system boot. The second entry allows log entries from the specified client. The `-v -v` increases the verbosity of logged messages. This is useful for tweaking facilities as administrators are able to see what type of messages are being logged under each facility. Multiple `-a` options may be specified to allow logging from multiple clients. IP addresses and whole netblocks may also be specified. Refer to man:syslogd[8] for a full list of possible options. Finally, create the log file: [source,shell] .... # touch /var/log/logclient.log .... At this point, syslogd should be restarted and verified: [source,shell] .... # service syslogd restart # pgrep syslog .... If a PID is returned, the server restarted successfully, and client configuration can begin. If the server did not restart, consult [.filename]#/var/log/messages# for the error. ==== Log Client Configuration A logging client sends log entries to a logging server on the network. The client also keeps a local copy of its own logs. Once a logging server has been configured, execute the following commands on the logging client: [source,shell] .... # sysrc syslogd_enable="YES" # sysrc syslogd_flags="-s -v -v" .... The first entry enables syslogd on boot up. The second entry prevents logs from being accepted by this client from other hosts (`-s`) and increases the verbosity of logged messages. Next, define the logging server in the client's [.filename]#/etc/syslog.conf#. In this example, all logged facilities are sent to a remote system, denoted by the `@` symbol, with the specified hostname: [.programlisting] .... *.* @logserv.example.com .... After saving the edit, restart syslogd for the changes to take effect: [source,shell] .... # service syslogd restart .... To test that log messages are being sent across the network, use man:logger[1] on the client to send a message to syslogd: [source,shell] .... # logger "Test message from logclient" .... This message should now exist both in [.filename]#/var/log/messages# on the client and [.filename]#/var/log/logclient.log# on the log server. ==== Debugging Log Servers If no messages are being received on the log server, the cause is most likely a network connectivity issue, a hostname resolution issue, or a typo in a configuration file. To isolate the cause, ensure that both the logging server and the logging client are able to `ping` each other using the hostname specified in their [.filename]#/etc/rc.conf#. If this fails, check the network cabling, the firewall ruleset, and the hostname entries in the DNS server or [.filename]#/etc/hosts# on both the logging server and clients. Repeat until the `ping` is successful from both hosts. If the `ping` succeeds on both hosts but log messages are still not being received, temporarily increase logging verbosity to narrow down the configuration issue. In the following example, [.filename]#/var/log/logclient.log# on the logging server is empty and [.filename]#/var/log/messages# on the logging client does not indicate a reason for the failure. To increase debugging output, edit the `syslogd_flags` entry on the logging server and issue a restart: [source,shell] .... sysrc syslogd_flags="-d -a logclient.example.com -v -v" .... [source,shell] .... # service syslogd restart .... Debugging data similar to the following will flash on the console immediately after the restart: [.programlisting] .... logmsg: pri 56, flags 4, from logserv.example.com, msg syslogd: restart syslogd: restarted logmsg: pri 6, flags 4, from logserv.example.com, msg syslogd: kernel boot file is /boot/kernel/kernel Logging to FILE /var/log/messages syslogd: kernel boot file is /boot/kernel/kernel cvthname(192.168.1.10) validate: dgram from IP 192.168.1.10, port 514, name logclient.example.com; rejected in rule 0 due to name mismatch. .... In this example, the log messages are being rejected due to a typo which results in a hostname mismatch. The client's hostname should be `logclient`, not `logclien`. Fix the typo, issue a restart, and verify the results: [source,shell] .... # service syslogd restart .... The output should be similar to the following: [.programlisting] .... logmsg: pri 56, flags 4, from logserv.example.com, msg syslogd: restart syslogd: restarted logmsg: pri 6, flags 4, from logserv.example.com, msg syslogd: kernel boot file is /boot/kernel/kernel syslogd: kernel boot file is /boot/kernel/kernel logmsg: pri 166, flags 17, from logserv.example.com, msg Dec 10 20:55:02 logserv.example.com syslogd: exiting on signal 2 cvthname(192.168.1.10) validate: dgram from IP 192.168.1.10, port 514, name logclient.example.com; accepted in rule 0. logmsg: pri 15, flags 0, from logclient.example.com, msg Dec 11 02:01:28 trhodes: Test message 2 Logging to FILE /var/log/logclient.log Logging to FILE /var/log/messages .... At this point, the messages are being properly received and placed in the correct file. ==== Security Considerations As with any network service, security requirements should be considered before implementing a logging server. Log files may contain sensitive data about services enabled on the local host, user accounts, and configuration data. Network data sent from the client to the server will not be encrypted or password protected. If a need for encryption exists, consider using package:security/stunnel[], which will transmit the logging data over an encrypted tunnel. Local security is also an issue. Log files are not encrypted during use or after log rotation. Local users may access log files to gain additional insight into system configuration. Setting proper permissions on log files is critical. The built-in log rotator, newsyslog, supports setting permissions on newly created and rotated log files. Setting log files to mode `600` should prevent unwanted access by local users. Refer to man:newsyslog.conf[5] for additional information. [[acpi-overview]] == Power and Resource Management It is important to utilize hardware resources in an efficient manner. Power and resource management allows the operating system to monitor system limits and to possibly run some actions triggered by events related to those limits. [[acpi-config]] === ACPI configuration On FreeBSD the management of these resources is managed by the man:acpi[4] kernel device. [NOTE] ==== In FreeBSD the man:acpi[4] driver is loaded by default at system boot. This driver *cannot be unloaded after boot* because the system bus uses it for various hardware interactions. ==== In addition to man:acpi[4], FreeBSD has several dedicated kernel modules for various ACPI vendor subsystems. These modules will add some extra functionality like fan speed, keyboard backlit or screen brightness. The list can be obtained by running the following command: [source,shell] .... % ls /boot/kernel | grep acpi .... The output should be similar to the following: [.programlisting] .... acpi_asus.ko acpi_asus_wmi.ko acpi_dock.ko acpi_fujitsu.ko acpi_hp.ko acpi_ibm.ko acpi_panasonic.ko acpi_sony.ko acpi_toshiba.ko acpi_video.ko acpi_wmi.ko sdhci_acpi.ko uacpi.ko .... In the event that, for example, an IBM/Lenovo laptop is used, it will be necessary to load the module man:acpi_ibm[4] by executing the following command: [source,shell] .... # kldload acpi_ibm .... And add this line to [.filename]#/boot/loader.conf# to load it at boot: [.programlisting] .... acpi_ibm_load="YES" .... An alternative to the man:acpi_video[4] module is the man:backlight[9] driver. It provides a generic way for handling a panel backlight. The default GENERIC kernel includes this driver. The man:backlight[8] utility can be used to query and adjust the brightness of the panel backlight. In this example the brightness is decreased by 10%: [source,shell] .... % backlight decr 10 .... [[cpu-power-management]] === CPU Power Management CPU is the most consuming part of the system. Knowing how to improve CPU efficiency is a fundamental part of our system in order to save energy. In order to make proper use of the machine's resources in a correct way, FreeBSD supports technologies such as Intel Turbo Boost, AMD Turbo Core, Intel Speed Shift among others through the use of man:powerd[8] and man:cpufreq[4]. The first step will be to obtain the CPU information by executing the following command: [source,shell] .... % sysctl dev.cpu.0 <.> .... <.> In this case the `0` digit represents the first core of the CPU. The output should be similar to the following: [.programlisting] .... dev.cpu.0.cx_method: C1/mwait/hwc C2/mwait/hwc C3/mwait/hwc/bma dev.cpu.0.cx_usage_counters: 3507294 0 0 dev.cpu.0.cx_usage: 100.00% 0.00% 0.00% last 3804us dev.cpu.0.cx_lowest: C3 <1> dev.cpu.0.cx_supported: C1/1/1 C2/2/1 C3/3/57 <2> dev.cpu.0.freq_levels: 2267/35000 2266/35000 1600/15000 800/12000 <3> dev.cpu.0.freq: 1600 <4> dev.cpu.0.temperature: 40.0C <5> dev.cpu.0.coretemp.throttle_log: 0 dev.cpu.0.coretemp.tjmax: 105.0C dev.cpu.0.coretemp.resolution: 1 dev.cpu.0.coretemp.delta: 65 dev.cpu.0.%parent: acpi0 dev.cpu.0.%pnpinfo: _HID=none _UID=0 _CID=none dev.cpu.0.%location: handle=\_PR_.CPU0 dev.cpu.0.%driver: cpu dev.cpu.0.%desc: ACPI CPU .... <1> Lowest Cx state to use for idling the CPU. <2> CPU supported Cx states. <3> Currently available levels for the CPU (frequency/power usage). <4> Current active CPU frequency in MHz. <5> Current temperature of the CPU. [NOTE] ==== If the temperature information is not displayed, load the man:coretemp[4] module. In case of using an AMD CPU, load the man:amdtemp[4] module. ==== Once the CPU information is available the easiest way to configure power saving is to let man:powerd[8] take over. Enable man:powerd[8] service in [.filename]#/etc/rc.conf# to start at system boot: [source,shell] .... # sysrc powerd_enable=YES .... It will also be necessary to indicate certain parameters to man:powerd[8] to tell it how to manage the state of the CPU executing the following command: [source,shell] .... # sysrc powerd_flags="-a hiadaptive -i 25 -r 85 -N" .... . `-a`: Selects the mode to use while on AC power. . `hiadaptive`: Operation mode. More info at man:powerd[8]. . `-i`: Specifies the CPU load percent level when adaptive mode should begin to degrade performance to save power. . `-r`: Specifies the CPU load percent level where adaptive mode should consider the CPU running and increase performance. . `-N`: Treat "nice" time as idle for the purpose of load calculation; i.e., do not increase the CPU frequency if the CPU is only busy with "nice" processes. And then enable the service executing the following command: [source,shell] .... # service powerd start .... [[cpufreq]] === CPU Frequency Control FreeBSD includes a generic man:cpufreq[4] driver to allow the administrator, or software such as man:powerd[8] and package:sysutils/powerdxx[], to manage the frequency of the CPU to achieve the desired balance between performance and economy. A lower setting will save power while reducing the heat generated by the CPU. A higher setting will increase performance at the cost of using additional power and generating more heat. [[est]] === Intel(R) Enhanced Speed Step(TM) The Intel(R) Enhanced Speed Step(TM) driver, man:est[4], replaces the generic man:cpufreq[4] driver for CPUs that provide this feature. The CPU frequency can be statically adjusted using man:sysctl[8], or with the `/etc/rc.d/power_profile` startup script. Additional software, such as man:powerd[8] or package:sysutils/powerdxx[], can be used to automatically adjust the CPU frequency based on processor utilization. Each supported frequency, along with its expected power consumption, can be listed by examining the man:sysctl[3] tree: [source,shell] .... # sysctl dev.cpufreq.0.freq_driver dev.cpu.0.freq_levels dev.cpu.0.freq .... The output should be similar to the following: [.programlisting] .... dev.cpufreq.0.freq_driver: est0 dev.cpu.0.freq_levels: 3001/53000 3000/53000 2900/50301 2700/46082 2600/43525 2400/39557 2300/37137 2100/33398 2000/31112 1800/27610 1700/25455 1500/22171 1400/20144 1200/17084 1100/15181 900/12329 800/10550 dev.cpu.0.freq: 800 .... A frequency 1 MHz higher than the maximum frequency of the CPU indicates the Intel(R) Turbo Boost(TM) feature. [[hwpstate_intel]] === Intel Speed Shift(TM) Users running newer Intel(R) CPUs may find some differences in dynamic frequency control when upgrading to FreeBSD 13. A new driver for the Intel(R) Speed Shift(TM) feature set, available on certain SKUs, exposes the ability for the hardware to dynamically vary the core frequencies, including on a per core basis. FreeBSD 13 comes with the man:hwpstate_intel[4] driver to automatically enable Speed Shift(TM) control on equipped CPUs, replacing the older Enhanced Speed Step(TM) man:est[4] driver. The man:sysctl[8] `dev.cpufreq.%d.freq_driver` will indicate if the system is using Speed Shift. To determine which frequency control driver is being used, examining the `dev.cpufreq.0.freq_driver` oid. [source,shell] .... # sysctl dev.cpufreq.0.freq_driver .... The output should be similar to the following: [.programlisting] .... dev.cpufreq.0.freq_driver: hwpstate_intel0 .... This indicates that the new man:hwpstate_intel[4] driver is in use. On such systems, the oid `dev.cpu.%d.freq_levels` will show only the maximum CPU frequency, and will indicate a power consumption level of `-1`. The current CPU frequency can be determined by examining the `dev.cpu.%d.freq` oid. [source,shell] .... # sysctl dev.cpu.0.freq_levels dev.cpu.0.freq .... The output should be similar to the following: [.programlisting] .... dev.cpu.0.freq_levels: 3696/-1 dev.cpu.0.freq: 898 .... For more information, including on how to balance performance and energy use, and on how to disable this driver, refer to the man page man:hwpstate_intel[4]. [NOTE] ==== Users accustomed to using man:powerd[8] or package:sysutils/powerdxx[] will find these utilities have been superseded by the man:hwpstate_intel[4] driver and no longer work as expected. ==== [[graphics-card-power-management]] === Graphics Card Power Management Graphics cards have become a fundamental part of computing in recent years. Some graphics cards may have excessive power consumption. FreeBSD allows certain configurations to improve power consumption. In case of using a Intel(R) graphics card with the package:graphics/drm-kmod[] driver these options can be added to [.filename]#/boot/loader.conf#: [.programlisting] .... compat.linuxkpi.fastboot=1 <.> compat.linuxkpi.enable_dc=2 <.> compat.linuxkpi.enable_fbc=1 <.> .... <.> Try to skip unnecessary mode sets at boot time. <.> Enable power-saving display C-states. <.> Enable frame buffer compression for power savings === Suspend/Resume The suspend/resume function allows the machine to be kept in a state in which there is no a big energy consumption and allows the system to be resumed without having to lose the state of the running programs. [NOTE] ==== In order for the suspend/resume functionality to work correctly the graphics drivers must be loaded on the system. In non-KMS-supported graphics cards man:sc[4] must be used not to break the suspend/resume functionality. More information about which driver to use and how to configure it can be found at the crossref:x11[x11, The X Window System chapter]. ==== man:acpi[4] supports the next list of sleep states: .Supported Sleep States [options="header", cols="1,1"] |=== |S1 |Quick suspend to RAM. The CPU enters a lower power state, but most peripherals are left running. |S2 |Lower power state than S1, but with the same basic characteristics. Not supported by many systems. |S3 (Sleep mode) |Suspend to RAM. Most devices are powered off, and the system stops running except for memory refresh. |S4 (Hibernation) |Suspend to disk. All devices are powered off, and the system stops running. When resuming, the system starts as if from a cold power on. *Not yet supported by FreeBSD*. |S5 |System shuts down cleanly and powers off. |=== [[configure-suspend-resume]] ==== Configuring Suspend/Resume The first step will be to know which type of sleep states supports the hardware we are using executing the following command: [source,shell] .... % sysctl hw.acpi.supported_sleep_state .... The output should be similar to the following: [.programlisting] .... hw.acpi.supported_sleep_state: S3 S4 S5 .... [WARNING] ==== As stated above FreeBSD does *not* yet support the `S4` state. ==== man:acpiconf[8] can be used to check if the `S3` state works correctly by running the following command, if it succeeds, the screen should go black and the machine will turn off: [source,shell] .... # acpiconf -s 3 .... In the vast majority of cases the Suspend/Resume functionality wants to be used on a laptop. FreeBSD can be configured to enter the `S3` state when closing the lid by adding the following line to the [.filename]#/etc/sysctl.conf# file. [.programlisting] .... hw.acpi.lid_switch_state=S3 .... [[troubleshooting-suspend-resume]] ==== Troubleshooting in Suspend/Resume A lot of effort has been made to make the Suspend and Resume functions work properly and in the best way on FreeBSD. But currently the Suspend and Resume functions only work properly on some specific laptops. Some checks can be done in case it doesn't work properly. In some cases it is enough to turn off the bluetooth. In others it is enough loading the correct driver for the graphics card, etc. In case it doesn't work correctly, some tips can be found on the FreeBSD Wiki in the section link:https://wiki.freebsd.org/SuspendResume[Suspend/Resume]. [[adding-swap-space]] == Adding Swap Space Sometimes a FreeBSD system requires more swap space. This section describes two methods to increase swap space: adding swap to an existing partition or new hard drive, and creating a swap file on an existing file system. For information on how to encrypt swap space, which options exist, and why it should be done, refer to crossref:disks[swap-encrypting,“Encrypting Swap”]. [[new-drive-swap]] === Swap on a New Hard Drive or Existing Partition Adding a new drive for swap gives better performance than using a partition on an existing drive. Setting up partitions and drives is explained in crossref:disks[disks-adding,"Adding Disks"] while crossref:bsdinstall[configtuning-initial,"Designing the Partition Layout"] discusses partition layouts and swap partition size considerations. [WARNING] ==== It is possible to use any partition not currently mounted, even if it already contains data. Using `swapon` on a partition that contains data will overwrite and destroy that data. Make sure that the partition to be added as swap is really the intended partition before running `swapon`. ==== man:swapon[8] can be used to add a swap partition to the system executing the following command: [source,shell] .... # swapon /dev/ada1p2 .... To automatically add this swap partition on boot, add an entry to [.filename]#/etc/fstab#: [.programlisting] .... /dev/ada1p2 none swap sw 0 0 .... See man:fstab[5] for an explanation of the entries in [.filename]#/etc/fstab#. [[create-swapfile]] === Creating a Swap File [[swapfile-10-and-later]] These examples create a 512M swap file called [.filename]#/usr/swap0#. [WARNING] ==== Swap files on ZFS file systems are strongly discouraged, as swapping can lead to system hangs. ==== The first step is to create the swap file: [source,shell] .... # dd if=/dev/zero of=/usr/swap0 bs=1m count=512 .... The second step is to put the proper permissions on the new file: [source,shell] .... # chmod 0600 /usr/swap0 .... The third step is to inform the system about the swap file by adding a line to [.filename]#/etc/fstab#: [.programlisting] .... md none swap sw,file=/usr/swap0,late 0 0 .... Swap space will be added on system startup. To add swap space immediately, use man:swapon[8]: [source,shell] .... # swapon -aL .... diff --git a/documentation/content/en/books/handbook/disks/_index.adoc b/documentation/content/en/books/handbook/disks/_index.adoc index b452036936..862d5c5f46 100644 --- a/documentation/content/en/books/handbook/disks/_index.adoc +++ b/documentation/content/en/books/handbook/disks/_index.adoc @@ -1,2557 +1,2556 @@ --- title: Chapter 20. Storage part: Part III. System Administration prev: books/handbook/audit next: books/handbook/geom description: This chapter covers the use of disks and storage media in FreeBSD. This includes SCSI and IDE disks, CD and DVD media, memory-backed disks, and USB storage devices. tags: ["storage", "disks", "gpart", "mount", "quotas", "encrypt", "GPT", "cdrecord", "NTFS", "quotas", "swap", "HAST", "CD", "DVD", "resizing", "growing"] showBookMenu: true weight: 24 path: "/books/handbook/" --- [[disks]] = Storage :doctype: book :toc: macro :toclevels: 1 :icons: font :sectnums: :sectnumlevels: 6 :sectnumoffset: 20 :partnums: :source-highlighter: rouge :experimental: :images-path: books/handbook/disks/ ifdef::env-beastie[] ifdef::backend-html5[] :imagesdir: ../../../../images/{images-path} endif::[] ifndef::book[] include::shared/authors.adoc[] include::shared/mirrors.adoc[] include::shared/releases.adoc[] include::shared/attributes/attributes-{{% lang %}}.adoc[] include::shared/{{% lang %}}/teams.adoc[] include::shared/{{% lang %}}/mailing-lists.adoc[] include::shared/{{% lang %}}/urls.adoc[] toc::[] endif::[] ifdef::backend-pdf,backend-epub3[] include::../../../../../shared/asciidoctor.adoc[] endif::[] endif::[] ifndef::env-beastie[] toc::[] include::../../../../../shared/asciidoctor.adoc[] endif::[] [[disks-synopsis]] == Synopsis This chapter covers the use of disks and storage media in FreeBSD. This includes SCSI and IDE disks, CD and DVD media, memory-backed disks, and USB storage devices. After reading this chapter, you will know: * How to add additional hard disks to a FreeBSD system. * How to grow the size of a disk's partition on FreeBSD. * How to configure FreeBSD to use USB storage devices. * How to use CD and DVD media on a FreeBSD system. * How to use the backup programs available under FreeBSD. * How to set up memory disks. * What file system snapshots are and how to use them efficiently. * How to use quotas to limit disk space usage. * How to encrypt disks and swap to secure them against attackers. * How to configure a highly available storage network. Before reading this chapter, you should: * Know how to crossref:kernelconfig[kernelconfig,configure and install a new FreeBSD kernel]. [[disks-adding]] == Adding Disks This section describes how to add a new SATA disk to a machine that currently only has a single drive. First, turn off the computer and install the drive in the computer following the instructions of the computer, controller, and drive manufacturers. Reboot the system and become `root`. Inspect [.filename]#/var/run/dmesg.boot# to ensure the new disk was found. In this example, the newly added SATA drive will appear as [.filename]#ada1#. For this example, a single large partition will be created on the new disk. The http://en.wikipedia.org/wiki/GUID_Partition_Table[GPT] partitioning scheme will be used in preference to the older and less versatile MBR scheme. [NOTE] ==== If the disk to be added is not blank, old partition information can be removed with `gpart delete`. See man:gpart[8] for details. ==== The partition scheme is created, and then a single partition is added. To improve performance on newer disks with larger hardware block sizes, the partition is aligned to one megabyte boundaries: [source,shell] .... # gpart create -s GPT ada1 # gpart add -t freebsd-ufs -a 1M ada1 .... Depending on use, several smaller partitions may be desired. See man:gpart[8] for options to create partitions smaller than a whole disk. The disk partition information can be viewed with `gpart show`: [source,shell] .... % gpart show ada1 => 34 1465146988 ada1 GPT (699G) 34 2014 - free - (1.0M) 2048 1465143296 1 freebsd-ufs (699G) 1465145344 1678 - free - (839K) .... A file system is created in the new partition on the new disk: [source,shell] .... # newfs -U /dev/ada1p1 .... An empty directory is created as a _mountpoint_, a location for mounting the new disk in the original disk's file system: [source,shell] .... # mkdir /newdisk .... Finally, an entry is added to [.filename]#/etc/fstab# so the new disk will be mounted automatically at startup: [.programlisting] .... /dev/ada1p1 /newdisk ufs rw 2 2 .... The new disk can be mounted manually, without restarting the system: [source,shell] .... # mount /newdisk .... [[disks-growing]] == Resizing and Growing Disks A disk's capacity can increase without any changes to the data already present. This happens commonly with virtual machines, when the virtual disk turns out to be too small and is enlarged. Sometimes a disk image is written to a USB memory stick, but does not use the full capacity. Here we describe how to resize or _grow_ disk contents to take advantage of increased capacity. Determine the device name of the disk to be resized by inspecting [.filename]#/var/run/dmesg.boot#. In this example, there is only one SATA disk in the system, so the drive will appear as [.filename]#ada0#. List the partitions on the disk to see the current configuration: [source,shell] .... # gpart show ada0 => 34 83886013 ada0 GPT (48G) [CORRUPT] 34 128 1 freebsd-boot (64k) 162 79691648 2 freebsd-ufs (38G) 79691810 4194236 3 freebsd-swap (2G) 83886046 1 - free - (512B) .... [NOTE] ==== If the disk was formatted with the http://en.wikipedia.org/wiki/GUID_Partition_Table[GPT] partitioning scheme, it may show as "corrupted" because the GPT backup partition table is no longer at the end of the drive. Fix the backup partition table with `gpart`: [source,shell] .... # gpart recover ada0 ada0 recovered .... ==== Now the additional space on the disk is available for use by a new partition, or an existing partition can be expanded: [source,shell] .... # gpart show ada0 => 34 102399933 ada0 GPT (48G) 34 128 1 freebsd-boot (64k) 162 79691648 2 freebsd-ufs (38G) 79691810 4194236 3 freebsd-swap (2G) 83886046 18513921 - free - (8.8G) .... Partitions can only be resized into contiguous free space. Here, the last partition on the disk is the swap partition, but the second partition is the one that needs to be resized. Swap partitions only contain temporary data, so it can safely be unmounted, deleted, and then recreate the third partition after resizing the second partition. Disable the swap partition: [source,shell] .... # swapoff /dev/ada0p3 .... Delete the third partition, specified by the `-i` flag, from the disk _ada0_. [source,shell] .... # gpart delete -i 3 ada0 ada0p3 deleted # gpart show ada0 => 34 102399933 ada0 GPT (48G) 34 128 1 freebsd-boot (64k) 162 79691648 2 freebsd-ufs (38G) 79691810 22708157 - free - (10G) .... [WARNING] ==== There is risk of data loss when modifying the partition table of a mounted file system. It is best to perform the following steps on an unmounted file system while running from a live CD-ROM or USB device. However, if absolutely necessary, a mounted file system can be resized after disabling GEOM safety features: [source,shell] .... # sysctl kern.geom.debugflags=16 .... ==== Resize the partition, leaving room to recreate a swap partition of the desired size. The partition to resize is specified with `-i`, and the new desired size with `-s`. Optionally, alignment of the partition is controlled with `-a`. This only modifies the size of the partition. The file system in the partition will be expanded in a separate step. [source,shell] .... # gpart resize -i 2 -s 47G -a 4k ada0 ada0p2 resized # gpart show ada0 => 34 102399933 ada0 GPT (48G) 34 128 1 freebsd-boot (64k) 162 98566144 2 freebsd-ufs (47G) 98566306 3833661 - free - (1.8G) .... Recreate the swap partition and activate it. If no size is specified with `-s`, all remaining space is used: [source,shell] .... # gpart add -t freebsd-swap -a 4k ada0 ada0p3 added # gpart show ada0 => 34 102399933 ada0 GPT (48G) 34 128 1 freebsd-boot (64k) 162 98566144 2 freebsd-ufs (47G) 98566306 3833661 3 freebsd-swap (1.8G) # swapon /dev/ada0p3 .... Grow the UFS file system to use the new capacity of the resized partition: [source,shell] .... # growfs /dev/ada0p2 Device is mounted read-write; resizing will result in temporary write suspension for /. It's strongly recommended to make a backup before growing the file system. OK to grow file system on /dev/ada0p2, mounted on /, from 38GB to 47GB? [Yes/No] Yes super-block backups (for fsck -b #) at: 80781312, 82063552, 83345792, 84628032, 85910272, 87192512, 88474752, 89756992, 91039232, 92321472, 93603712, 94885952, 96168192, 97450432 .... If the file system is ZFS, the resize is triggered by running the `online` subcommand with `-e`: [source,shell] .... # zpool online -e zroot /dev/ada0p2 .... Both the partition and the file system on it have now been resized to use the newly-available disk space. [[usb-disks]] == USB Storage Devices Many external storage solutions, such as hard drives, USB thumbdrives, and CD and DVD burners, use the Universal Serial Bus (USB). FreeBSD provides support for USB 1.x, 2.0, and 3.0 devices. [NOTE] ==== USB 3.0 support is not compatible with some hardware, including Haswell (Lynx point) chipsets. If FreeBSD boots with a `failed with error 19` message, disable xHCI/USB3 in the system BIOS. ==== Support for USB storage devices is built into the [.filename]#GENERIC# kernel. For a custom kernel, be sure that the following lines are present in the kernel configuration file: [.programlisting] .... device scbus # SCSI bus (required for ATA/SCSI) device da # Direct Access (disks) device pass # Passthrough device (direct ATA/SCSI access) device uhci # provides USB 1.x support device ohci # provides USB 1.x support device ehci # provides USB 2.0 support device xhci # provides USB 3.0 support device usb # USB Bus (required) device umass # Disks/Mass storage - Requires scbus and da device cd # needed for CD and DVD burners .... FreeBSD uses the man:umass[4] driver which uses the SCSI subsystem to access USB storage devices. Since any USB device will be seen as a SCSI device by the system, if the USB device is a CD or DVD burner, do _not_ include `device atapicam` in a custom kernel configuration file. The rest of this section demonstrates how to verify that a USB storage device is recognized by FreeBSD and how to configure the device so that it can be used. === Device Configuration To test the USB configuration, plug in the USB device. Use `dmesg` to confirm that the drive appears in the system message buffer. It should look something like this: [source,shell] .... umass0: on usbus0 umass0: SCSI over Bulk-Only; quirks = 0x0100 umass0:4:0:-1: Attached to scbus4 da0 at umass-sim0 bus 0 scbus4 target 0 lun 0 da0: Fixed Direct Access SCSI-4 device da0: Serial Number WD-WXE508CAN263 da0: 40.000MB/s transfers da0: 152627MB (312581808 512 byte sectors: 255H 63S/T 19457C) da0: quirks=0x2 .... The brand, device node ([.filename]#da0#), speed, and size will differ according to the device. Since the USB device is seen as a SCSI one, `camcontrol` can be used to list the USB storage devices attached to the system: [source,shell] .... # camcontrol devlist at scbus4 target 0 lun 0 (pass3,da0) .... Alternately, `usbconfig` can be used to list the device. Refer to man:usbconfig[8] for more information about this command. [source,shell] .... # usbconfig ugen0.3: at usbus0, cfg=0 md=HOST spd=HIGH (480Mbps) pwr=ON (2mA) .... If the device has not been formatted, refer to <> for instructions on how to format and create partitions on the USB drive. If the drive comes with a file system, it can be mounted by `root` using the instructions in crossref:basics[mount-unmount,“Mounting and Unmounting File Systems”]. [WARNING] ==== Allowing untrusted users to mount arbitrary media, by enabling `vfs.usermount` as described below, should not be considered safe from a security point of view. Most file systems were not built to safeguard against malicious devices. ==== To make the device mountable as a normal user, one solution is to make all users of the device a member of the `operator` group using man:pw[8]. Next, ensure that `operator` is able to read and write the device by adding these lines to [.filename]#/etc/devfs.rules#: [.programlisting] .... [localrules=5] add path 'da*' mode 0660 group operator .... [NOTE] ==== If internal SCSI disks are also installed in the system, change the second line as follows: [.programlisting] .... add path 'da[3-9]*' mode 0660 group operator .... This will exclude the first three SCSI disks ([.filename]#da0# to [.filename]#da2#) from belonging to the `operator` group. Replace _3_ with the number of internal SCSI disks. Refer to man:devfs.rules[5] for more information about this file. ==== Next, enable the ruleset in [.filename]#/etc/rc.conf#: [.programlisting] .... devfs_system_ruleset="localrules" .... Then, instruct the system to allow regular users to mount file systems by adding the following line to [.filename]#/etc/sysctl.conf#: [.programlisting] .... vfs.usermount=1 .... Since this only takes effect after the next reboot, use `sysctl` to set this variable now: [source,shell] .... # sysctl vfs.usermount=1 vfs.usermount: 0 -> 1 .... The final step is to create a directory where the file system is to be mounted. This directory needs to be owned by the user that is to mount the file system. One way to do that is for `root` to create a subdirectory owned by that user as [.filename]#/mnt/username#. In the following example, replace _username_ with the login name of the user and _usergroup_ with the user's primary group: [source,shell] .... # mkdir /mnt/username # chown username:usergroup /mnt/username .... Suppose a USB thumbdrive is plugged in, and a device [.filename]#/dev/da0s1# appears. If the device is formatted with a FAT file system, the user can mount it using: [source,shell] .... % mount -t msdosfs -o -m=644,-M=755 /dev/da0s1 /mnt/username .... Before the device can be unplugged, it _must_ be unmounted first: [source,shell] .... % umount /mnt/username .... After device removal, the system message buffer will show messages similar to the following: [source,shell] .... umass0: at uhub3, port 2, addr 3 (disconnected) da0 at umass-sim0 bus 0 scbus4 target 0 lun 0 da0: s/n WD-WXE508CAN263 detached (da0:umass-sim0:0:0:0): Periph destroyed .... === Automounting Removable Media USB devices can be automatically mounted by uncommenting this line in [.filename]#/etc/auto_master#: [source,shell] .... /media -media -nosuid .... Then add these lines to [.filename]#/etc/devd.conf#: [source,shell] .... notify 100 { match "system" "GEOM"; match "subsystem" "DEV"; action "/usr/sbin/automount -c"; }; .... Reload the configuration if man:autofs[5] and man:devd[8] are already running: [source,shell] .... # service automount restart # service devd restart .... man:autofs[5] can be set to start at boot by adding this line to [.filename]#/etc/rc.conf#: [.programlisting] .... autofs_enable="YES" .... man:autofs[5] requires man:devd[8] to be enabled, as it is by default. Start the services immediately with: [source,shell] .... # service automount start # service automountd start # service autounmountd start # service devd start .... Each file system that can be automatically mounted appears as a directory in [.filename]#/media/#. The directory is named after the file system label. If the label is missing, the directory is named after the device node. The file system is transparently mounted on the first access, and unmounted after a period of inactivity. Automounted drives can also be unmounted manually: [source,shell] .... # automount -fu .... This mechanism is typically used for memory cards and USB memory sticks. It can be used with any block device, including optical drives or iSCSILUNs. [[creating-cds]] == Creating and Using CD Media Compact Disc (CD) media provide a number of features that differentiate them from conventional disks. They are designed so that they can be read continuously without delays to move the head between tracks. While CD media do have tracks, these refer to a section of data to be read continuously, and not a physical property of the disk. The ISO 9660 file system was designed to deal with these differences. The FreeBSD Ports Collection provides several utilities for burning and duplicating audio and data CDs. This chapter demonstrates the use of several command line utilities. For CD burning software with a graphical utility, consider installing the package:sysutils/xcdroast[] or package:sysutils/k3b[] packages or ports. [[atapicam]] === Supported Devices The [.filename]#GENERIC# kernel provides support for SCSI, USB, and ATAPICD readers and burners. If a custom kernel is used, the options that need to be present in the kernel configuration file vary by the type of device. For a SCSI burner, make sure these options are present: [.programlisting] .... device scbus # SCSI bus (required for ATA/SCSI) device da # Direct Access (disks) device pass # Passthrough device (direct ATA/SCSI access) device cd # needed for CD and DVD burners .... For a USB burner, make sure these options are present: [.programlisting] .... device scbus # SCSI bus (required for ATA/SCSI) device da # Direct Access (disks) device pass # Passthrough device (direct ATA/SCSI access) device cd # needed for CD and DVD burners device uhci # provides USB 1.x support device ohci # provides USB 1.x support device ehci # provides USB 2.0 support device xhci # provides USB 3.0 support device usb # USB Bus (required) device umass # Disks/Mass storage - Requires scbus and da .... For an ATAPI burner, make sure these options are present: [.programlisting] .... device ata # Legacy ATA/SATA controllers device scbus # SCSI bus (required for ATA/SCSI) device pass # Passthrough device (direct ATA/SCSI access) device cd # needed for CD and DVD burners .... [NOTE] ==== On FreeBSD versions prior to 10.x, this line is also needed in the kernel configuration file if the burner is an ATAPI device: [.programlisting] .... device atapicam .... Alternately, this driver can be loaded at boot time by adding the following line to [.filename]#/boot/loader.conf#: [.programlisting] .... atapicam_load="YES" .... This will require a reboot of the system as this driver can only be loaded at boot time. ==== To verify that FreeBSD recognizes the device, run `dmesg` and look for an entry for the device. On systems prior to 10.x, the device name in the first line of the output will be [.filename]#acd0# instead of [.filename]#cd0#. [source,shell] .... % dmesg | grep cd cd0 at ahcich1 bus 0 scbus1 target 0 lun 0 cd0: Removable CD-ROM SCSI-0 device cd0: Serial Number M3OD3S34152 cd0: 150.000MB/s transfers (SATA 1.x, UDMA6, ATAPI 12bytes, PIO 8192bytes) cd0: Attempt to query device size failed: NOT READY, Medium not present - tray closed .... [[cdrecord]] === Burning a CD In FreeBSD, `cdrecord` can be used to burn CDs. This command is installed with the package:sysutils/cdrtools[] package or port. While `cdrecord` has many options, basic usage is simple. Specify the name of the ISO file to burn and, if the system has multiple burner devices, specify the name of the device to use: [source,shell] .... # cdrecord dev=device imagefile.iso .... To determine the device name of the burner, use `-scanbus` which might produce results like this: [source,shell] .... # cdrecord -scanbus ProDVD-ProBD-Clone 3.00 (amd64-unknown-freebsd10.0) Copyright (C) 1995-2010 Jörg Schilling Using libscg version 'schily-0.9' scsibus0: 0,0,0 0) 'SEAGATE ' 'ST39236LW ' '0004' Disk 0,1,0 1) 'SEAGATE ' 'ST39173W ' '5958' Disk 0,2,0 2) * 0,3,0 3) 'iomega ' 'jaz 1GB ' 'J.86' Removable Disk 0,4,0 4) 'NEC ' 'CD-ROM DRIVE:466' '1.26' Removable CD-ROM 0,5,0 5) * 0,6,0 6) * 0,7,0 7) * scsibus1: 1,0,0 100) * 1,1,0 101) * 1,2,0 102) * 1,3,0 103) * 1,4,0 104) * 1,5,0 105) 'YAMAHA ' 'CRW4260 ' '1.0q' Removable CD-ROM 1,6,0 106) 'ARTEC ' 'AM12S ' '1.06' Scanner 1,7,0 107) * .... Locate the entry for the CD burner and use the three numbers separated by commas as the value for `dev`. In this case, the Yamaha burner device is `1,5,0`, so the appropriate input to specify that device is `dev=1,5,0`. Refer to the manual page for `cdrecord` for other ways to specify this value and for information on writing audio tracks and controlling the write speed. Alternately, run the following command to get the device address of the burner: [source,shell] .... # camcontrol devlist at scbus1 target 0 lun 0 (cd0,pass0) .... Use the numeric values for `scbus`, `target`, and `lun`. For this example, `1,0,0` is the device name to use. [[mkisofs]] === Writing Data to an ISO File System In order to produce a data CD, the data files that are going to make up the tracks on the CD must be prepared before they can be burned to the CD. In FreeBSD, package:sysutils/cdrtools[] installs `mkisofs`, which can be used to produce an ISO 9660 file system that is an image of a directory tree within a UNIX(R) file system. The simplest usage is to specify the name of the ISO file to create and the path to the files to place into the ISO 9660 file system: [source,shell] .... # mkisofs -o imagefile.iso /path/to/tree .... This command maps the file names in the specified path to names that fit the limitations of the standard ISO 9660 file system, and will exclude files that do not meet the standard for ISO file systems. A number of options are available to overcome the restrictions imposed by the standard. In particular, `-R` enables the Rock Ridge extensions common to UNIX(R) systems and `-J` enables Joliet extensions used by Microsoft(R) systems. For CDs that are going to be used only on FreeBSD systems, `-U` can be used to disable all filename restrictions. When used with `-R`, it produces a file system image that is identical to the specified FreeBSD tree, even if it violates the ISO 9660 standard. The last option of general use is `-b`. This is used to specify the location of a boot image for use in producing an "El Torito" bootable CD. This option takes an argument which is the path to a boot image from the top of the tree being written to the CD. By default, `mkisofs` creates an ISO image in "floppy disk emulation" mode, and thus expects the boot image to be exactly 1200, 1440 or 2880 KB in size. Some boot loaders, like the one used by the FreeBSD distribution media, do not use emulation mode. In this case, `-no-emul-boot` should be used. So, if [.filename]#/tmp/myboot# holds a bootable FreeBSD system with the boot image in [.filename]#/tmp/myboot/boot/cdboot#, this command would produce [.filename]#/tmp/bootable.iso#: [source,shell] .... # mkisofs -R -no-emul-boot -b boot/cdboot -o /tmp/bootable.iso /tmp/myboot .... The resulting ISO image can be mounted as a memory disk with: [source,shell] .... # mdconfig -a -t vnode -f /tmp/bootable.iso -u 0 # mount -t cd9660 /dev/md0 /mnt .... One can then verify that [.filename]#/mnt# and [.filename]#/tmp/myboot# are identical. There are many other options available for `mkisofs` to fine-tune its behavior. Refer to man:mkisofs[8] for details. [NOTE] ==== It is possible to copy a data CD to an image file that is functionally equivalent to the image file created with `mkisofs`. To do so, use [.filename]#dd# with the device name as the input file and the name of the ISO to create as the output file: [source,shell] .... # dd if=/dev/cd0 of=file.iso bs=2048 .... The resulting image file can be burned to CD as described in <>. ==== [[mounting-cd]] === Using Data CDs Once an ISO has been burned to a CD, it can be mounted by specifying the file system type, the name of the device containing the CD, and an existing mount point: [source,shell] .... # mount -t cd9660 /dev/cd0 /mnt .... Since `mount` assumes that a file system is of type `ufs`, an `Incorrect super block` error will occur if `-t cd9660` is not included when mounting a data CD. While any data CD can be mounted this way, disks with certain ISO 9660 extensions might behave oddly. For example, Joliet disks store all filenames in two-byte Unicode characters. If some non-English characters show up as question marks, specify the local charset with `-C`. For more information, refer to man:mount_cd9660[8]. [NOTE] ==== In order to do this character conversion with the help of `-C`, the kernel requires the [.filename]#cd9660_iconv.ko# module to be loaded. This can be done either by adding this line to [.filename]#loader.conf#: [.programlisting] .... cd9660_iconv_load="YES" .... and then rebooting the machine, or by directly loading the module with `kldload`. ==== Occasionally, `Device not configured` will be displayed when trying to mount a data CD. This usually means that the CD drive has not detected a disk in the tray, or that the drive is not visible on the bus. It can take a couple of seconds for a CD drive to detect media, so be patient. Sometimes, a SCSICD drive may be missed because it did not have enough time to answer the bus reset. To resolve this, a custom kernel can be created which increases the default SCSI delay. Add the following option to the custom kernel configuration file and rebuild the kernel using the instructions in crossref:kernelconfig[kernelconfig-building,“Building and Installing a Custom Kernel”]: [.programlisting] .... options SCSI_DELAY=15000 .... This tells the SCSI bus to pause 15 seconds during boot, to give the CD drive every possible chance to answer the bus reset. [NOTE] ==== It is possible to burn a file directly to CD, without creating an ISO 9660 file system. This is known as burning a raw data CD and some people do this for backup purposes. This type of disk can not be mounted as a normal data CD. In order to retrieve the data burned to such a CD, the data must be read from the raw device node. For example, this command will extract a compressed tar file located on the second CD device into the current working directory: [source,shell] .... # tar xzvf /dev/cd1 .... In order to mount a data CD, the data must be written using `mkisofs`. ==== [[duplicating-audiocds]] === Duplicating Audio CDs To duplicate an audio CD, extract the audio data from the CD to a series of files, then write these files to a blank CD. <> describes how to duplicate and burn an audio CD. If the FreeBSD version is less than 10.0 and the device is ATAPI, the `atapicam` module must be first loaded using the instructions in <>. [[using-cdrecord]] [.procedure] .Procedure: Duplicating an Audio CD . The package:sysutils/cdrtools[] package or port installs `cdda2wav`. This command can be used to extract all of the audio tracks, with each track written to a separate WAV file in the current working directory: + [source,shell] .... % cdda2wav -vall -B -Owav .... + A device name does not need to be specified if there is only one CD device on the system. Refer to the `cdda2wav` manual page for instructions on how to specify a device and to learn more about the other options available for this command. . Use `cdrecord` to write the [.filename]#.wav# files: + [source,shell] .... % cdrecord -v dev=2,0 -dao -useinfo *.wav .... + Make sure that _2,0_ is set appropriately, as described in <>. [[creating-dvds]] == Creating and Using DVD Media Compared to the CD, the DVD is the next generation of optical media storage technology. The DVD can hold more data than any CD and is the standard for video publishing. Five physical recordable formats can be defined for a recordable DVD: * DVD-R: This was the first DVD recordable format available. The DVD-R standard is defined by the http://www.dvdforum.org/forum.shtml[DVD Forum]. This format is write once. * DVD-RW: This is the rewritable version of the DVD-R standard. A DVD-RW can be rewritten about 1000 times. * DVD-RAM: This is a rewritable format which can be seen as a removable hard drive. However, this media is not compatible with most DVD-ROM drives and DVD-Video players as only a few DVD writers support the DVD-RAM format. Refer to <> for more information on DVD-RAM use. * DVD+RW: This is a rewritable format defined by the https://en.wikipedia.org/wiki/DVD%2BRW_Alliance[DVD+RW Alliance]. A DVD+RW can be rewritten about 1000 times. * DVD+R: This format is the write once variation of the DVD+RW format. A single layer recordable DVD can hold up to 4,700,000,000 bytes which is actually 4.38 GB or 4485 MB as 1 kilobyte is 1024 bytes. [NOTE] ==== A distinction must be made between the physical media and the application. For example, a DVD-Video is a specific file layout that can be written on any recordable DVD physical media such as DVD-R, DVD+R, or DVD-RW. Before choosing the type of media, ensure that both the burner and the DVD-Video player are compatible with the media under consideration. ==== === Configuration To perform DVD recording, use man:growisofs[1]. This command is part of the package:sysutils/dvd+rw-tools[] utilities which support all DVD media types. These tools use the SCSI subsystem to access the devices, therefore <> must be loaded or statically compiled into the kernel. This support is not needed if the burner uses the USB interface. Refer to <> for more details on USB device configuration. DMA access must also be enabled for ATAPI devices, by adding the following line to [.filename]#/boot/loader.conf#: [.programlisting] .... hw.ata.atapi_dma="1" .... Before attempting to use dvd+rw-tools, consult the http://fy.chalmers.se/~appro/linux/DVD+RW/hcn.html[Hardware Compatibility Notes]. [NOTE] ==== For a graphical user interface, consider using package:sysutils/k3b[] which provides a user friendly interface to man:growisofs[1] and many other burning tools. ==== === Burning Data DVDs Since man:growisofs[1] is a front-end to <>, it will invoke man:mkisofs[8] to create the file system layout and perform the write on the DVD. This means that an image of the data does not need to be created before the burning process. To burn to a DVD+R or a DVD-R the data in [.filename]#/path/to/data#, use the following command: [source,shell] .... # growisofs -dvd-compat -Z /dev/cd0 -J -R /path/to/data .... In this example, `-J -R` is passed to man:mkisofs[8] to create an ISO 9660 file system with Joliet and Rock Ridge extensions. Refer to man:mkisofs[8] for more details. For the initial session recording, `-Z` is used for both single and multiple sessions. Replace _/dev/cd0_, with the name of the DVD device. Using `-dvd-compat` indicates that the disk will be closed and that the recording will be unappendable. This should also provide better media compatibility with DVD-ROM drives. To burn a pre-mastered image, such as _imagefile.iso_, use: [source,shell] .... # growisofs -dvd-compat -Z /dev/cd0=imagefile.iso .... The write speed should be detected and automatically set according to the media and the drive being used. To force the write speed, use `-speed=`. Refer to man:growisofs[1] for example usage. [NOTE] ==== In order to support working files larger than 4.38GB, an UDF/ISO-9660 hybrid file system must be created by passing `-udf -iso-level 3` to man:mkisofs[8] and all related programs, such as man:growisofs[1]. This is required only when creating an ISO image file or when writing files directly to a disk. Since a disk created this way must be mounted as an UDF file system with man:mount_udf[8], it will be usable only on an UDF aware operating system. Otherwise it will look as if it contains corrupted files. To create this type of ISO file: [source,shell] .... % mkisofs -R -J -udf -iso-level 3 -o imagefile.iso /path/to/data .... To burn files directly to a disk: [source,shell] .... # growisofs -dvd-compat -udf -iso-level 3 -Z /dev/cd0 -J -R /path/to/data .... When an ISO image already contains large files, no additional options are required for man:growisofs[1] to burn that image on a disk. Be sure to use an up-to-date version of package:sysutils/cdrtools[], which contains man:mkisofs[8], as an older version may not contain large files support. If the latest version does not work, install package:sysutils/cdrtools-devel[] and read its man:mkisofs[8]. ==== === Burning a DVD-Video A DVD-Video is a specific file layout based on the ISO 9660 and micro-UDF (M-UDF) specifications. Since DVD-Video presents a specific data structure hierarchy, a particular program such as package:multimedia/dvdauthor[] is needed to author the DVD. If an image of the DVD-Video file system already exists, it can be burned in the same way as any other image. If `dvdauthor` was used to make the DVD and the result is in [.filename]#/path/to/video#, the following command should be used to burn the DVD-Video: [source,shell] .... # growisofs -Z /dev/cd0 -dvd-video /path/to/video .... `-dvd-video` is passed to man:mkisofs[8] to instruct it to create a DVD-Video file system layout. This option implies the `-dvd-compat` man:growisofs[1] option. === Using a DVD+RW Unlike CD-RW, a virgin DVD+RW needs to be formatted before first use. It is _recommended_ to let man:growisofs[1] take care of this automatically whenever appropriate. However, it is possible to use `dvd+rw-format` to format the DVD+RW: [source,shell] .... # dvd+rw-format /dev/cd0 .... Only perform this operation once and keep in mind that only virgin DVD+RW medias need to be formatted. Once formatted, the DVD+RW can be burned as usual. To burn a totally new file system and not just append some data onto a DVD+RW, the media does not need to be blanked first. Instead, write over the previous recording like this: [source,shell] .... # growisofs -Z /dev/cd0 -J -R /path/to/newdata .... The DVD+RW format supports appending data to a previous recording. This operation consists of merging a new session to the existing one as it is not considered to be multi-session writing. man:growisofs[1] will _grow_ the ISO 9660 file system present on the media. For example, to append data to a DVD+RW, use the following: [source,shell] .... # growisofs -M /dev/cd0 -J -R /path/to/nextdata .... The same man:mkisofs[8] options used to burn the initial session should be used during next writes. [NOTE] ==== Use `-dvd-compat` for better media compatibility with DVD-ROM drives. When using DVD+RW, this option will not prevent the addition of data. ==== To blank the media, use: [source,shell] .... # growisofs -Z /dev/cd0=/dev/zero .... === Using a DVD-RW A DVD-RW accepts two disc formats: incremental sequential and restricted overwrite. By default, DVD-RW discs are in sequential format. A virgin DVD-RW can be directly written without being formatted. However, a non-virgin DVD-RW in sequential format needs to be blanked before writing a new initial session. To blank a DVD-RW in sequential mode: [source,shell] .... # dvd+rw-format -blank=full /dev/cd0 .... [NOTE] ==== A full blanking using `-blank=full` will take about one hour on a 1x media. A fast blanking can be performed using `-blank`, if the DVD-RW will be recorded in Disk-At-Once (DAO) mode. To burn the DVD-RW in DAO mode, use the command: [source,shell] .... # growisofs -use-the-force-luke=dao -Z /dev/cd0=imagefile.iso .... Since man:growisofs[1] automatically attempts to detect fast blanked media and engage DAO write, `-use-the-force-luke=dao` should not be required. One should instead use restricted overwrite mode with any DVD-RW as this format is more flexible than the default of incremental sequential. ==== To write data on a sequential DVD-RW, use the same instructions as for the other DVD formats: [source,shell] .... # growisofs -Z /dev/cd0 -J -R /path/to/data .... To append some data to a previous recording, use `-M` with man:growisofs[1]. However, if data is appended on a DVD-RW in incremental sequential mode, a new session will be created on the disc and the result will be a multi-session disc. A DVD-RW in restricted overwrite format does not need to be blanked before a new initial session. Instead, overwrite the disc with `-Z`. It is also possible to grow an existing ISO 9660 file system written on the disc with `-M`. The result will be a one-session DVD. To put a DVD-RW in restricted overwrite format, the following command must be used: [source,shell] .... # dvd+rw-format /dev/cd0 .... To change back to sequential format, use: [source,shell] .... # dvd+rw-format -blank=full /dev/cd0 .... === Multi-Session Few DVD-ROM drives support multi-session DVDs and most of the time only read the first session. DVD+R, DVD-R and DVD-RW in sequential format can accept multiple sessions. The notion of multiple sessions does not exist for the DVD+RW and the DVD-RW restricted overwrite formats. Using the following command after an initial non-closed session on a DVD+R, DVD-R, or DVD-RW in sequential format, will add a new session to the disc: [source,shell] .... # growisofs -M /dev/cd0 -J -R /path/to/nextdata .... Using this command with a DVD+RW or a DVD-RW in restricted overwrite mode will append data while merging the new session to the existing one. The result will be a single-session disc. Use this method to add data after an initial write on these types of media. [NOTE] ==== Since some space on the media is used between each session to mark the end and start of sessions, one should add sessions with a large amount of data to optimize media space. The number of sessions is limited to 154 for a DVD+R, about 2000 for a DVD-R, and 127 for a DVD+R Double Layer. ==== === For More Information To obtain more information about a DVD, use `dvd+rw-mediainfo _/dev/cd0_` while the disc in the specified drive. More information about dvd+rw-tools can be found in man:growisofs[1], on the http://fy.chalmers.se/~appro/linux/DVD+RW/[dvd+rw-tools web site], and in the http://lists.debian.org/cdwrite/[cdwrite mailing list] archives. [NOTE] ==== When creating a problem report related to the use of dvd+rw-tools, always include the output of `dvd+rw-mediainfo`. ==== [[creating-dvd-ram]] === Using a DVD-RAM DVD-RAM writers can use either a SCSI or ATAPI interface. For ATAPI devices, DMA access has to be enabled by adding the following line to [.filename]#/boot/loader.conf#: [.programlisting] .... hw.ata.atapi_dma="1" .... A DVD-RAM can be seen as a removable hard drive. Like any other hard drive, the DVD-RAM must be formatted before it can be used. In this example, the whole disk space will be formatted with a standard UFS2 file system: [source,shell] .... # dd if=/dev/zero of=/dev/acd0 bs=2k count=1 # bsdlabel -Bw acd0 # newfs /dev/acd0 .... The DVD device, [.filename]#acd0#, must be changed according to the configuration. Once the DVD-RAM has been formatted, it can be mounted as a normal hard drive: [source,shell] .... # mount /dev/acd0 /mnt .... Once mounted, the DVD-RAM will be both readable and writeable. [[floppies]] == Creating and Using Floppy Disks This section explains how to format a 3.5 inch floppy disk in FreeBSD. [.procedure] ==== *Procedure: Steps to Format a Floppy* A floppy disk needs to be low-level formatted before it can be used. This is usually done by the vendor, but formatting is a good way to check media integrity. To low-level format the floppy disk on FreeBSD, use man:fdformat[1]. When using this utility, make note of any error messages, as these can help determine if the disk is good or bad. . To format the floppy, insert a new 3.5 inch floppy disk into the first floppy drive and issue: + [source,shell] .... # /usr/sbin/fdformat -f 1440 /dev/fd0 .... + . After low-level formatting the disk, create a disk label as it is needed by the system to determine the size of the disk and its geometry. The supported geometry values are listed in [.filename]#/etc/disktab#. + To write the disk label, use man:bsdlabel[8]: + [source,shell] .... # /sbin/bsdlabel -B -w /dev/fd0 fd1440 .... + . The floppy is now ready to be high-level formatted with a file system. The floppy's file system can be either UFS or FAT, where FAT is generally a better choice for floppies. + To format the floppy with FAT, issue: + [source,shell] .... # /sbin/newfs_msdos /dev/fd0 .... ==== The disk is now ready for use. To use the floppy, mount it with man:mount_msdosfs[8]. One can also install and use package:emulators/mtools[] from the Ports Collection. [[using-ntfs]] == Using NTFS Disks This section explains how to mount NTFS disks in FreeBSD. NTFS (New Technology File System) is a proprietary journaling file system developed by Microsoft(R). It has been the default file system in Microsoft Windows(R) for many years. FreeBSD can mount NTFS volumes using a FUSE file system. These file systems are implemented as user space programs which interact with the man:fusefs[5] kernel module via a well defined interface. [.procedure] ==== *Procedure: Steps to Mount a NTFS Disk* . Before using a FUSE file system we need to load the man:fusefs[5] kernel module: + [source,shell] .... # kldload fusefs .... + Use man:sysrc[8] to load the module at startup: + [source,shell] .... # sysrc kld_list+=fusefs .... . Install the actual NTFS file system from packages as in the example (see crossref:ports[pkgng-intro,Using pkg for Binary Package Management]) or from ports (see crossref:ports[ports-using,Using the Ports Collection]): + [source,shell] .... # pkg install fusefs-ntfs .... . Last we need to create a directory where the file system will be mounted: + [source,shell] .... # mkdir /mnt/usb .... . Suppose a USB disk is plugged in. The disk partition information can be viewed with man:gpart[8]: + [source,shell] .... # gpart show da0 => 63 1953525105 da0 MBR (932G) 63 1953525105 1 ntfs (932G) .... . We can mount the disk using the following command: + [source,shell] .... # ntfs-3g /dev/da0s1 /mnt/usb/ .... The disk is now ready to use. + . Additionally, an entry can be added to /etc/fstab: + [.programlisting] .... /dev/da0s1 /mnt/usb ntfs mountprog=/usr/local/bin/ntfs-3g,noauto,rw 0 0 .... + Now the disk can be now mounted with: + [source,shell] .... # mount /mnt/usb .... . The disk can be unmounted with: + [source,shell] .... # umount /mnt/usb/ .... ==== [[backup-basics]] == Backup Basics Implementing a backup plan is essential in order to have the ability to recover from disk failure, accidental file deletion, random file corruption, or complete machine destruction, including destruction of on-site backups. The backup type and schedule will vary, depending upon the importance of the data, the granularity needed for file restores, and the amount of acceptable downtime. Some possible backup techniques include: * Archives of the whole system, backed up onto permanent, off-site media. This provides protection against all of the problems listed above, but is slow and inconvenient to restore from, especially for non-privileged users. * File system snapshots, which are useful for restoring deleted files or previous versions of files. * Copies of whole file systems or disks which are synchronized with another system on the network using a scheduled package:net/rsync[]. * Hardware or software RAID, which minimizes or avoids downtime when a disk fails. Typically, a mix of backup techniques is used. For example, one could create a schedule to automate a weekly, full system backup that is stored off-site and to supplement this backup with hourly ZFS snapshots. In addition, one could make a manual backup of individual directories or files before making file edits or deletions. This section describes some of the utilities which can be used to create and manage backups on a FreeBSD system. === File System Backups The traditional UNIX(R) programs for backing up a file system are man:dump[8], which creates the backup, and man:restore[8], which restores the backup. These utilities work at the disk block level, below the abstractions of the files, links, and directories that are created by file systems. Unlike other backup software, `dump` backs up an entire file system and is unable to backup only part of a file system or a directory tree that spans multiple file systems. Instead of writing files and directories, `dump` writes the raw data blocks that comprise files and directories. [NOTE] ==== If `dump` is used on the root directory, it will not back up [.filename]#/home#, [.filename]#/usr# or many other directories since these are typically mount points for other file systems or symbolic links into those file systems. ==== When used to restore data, `restore` stores temporary files in [.filename]#/tmp/# by default. When using a recovery disk with a small [.filename]#/tmp#, set `TMPDIR` to a directory with more free space in order for the restore to succeed. When using `dump`, be aware that some quirks remain from its early days in Version 6 of AT&T UNIX(R),circa 1975. The default parameters assume a backup to a 9-track tape, rather than to another type of media or to the high-density tapes available today. These defaults must be overridden on the command line. It is possible to backup a file system across the network to a another system or to a tape drive attached to another computer. While the man:rdump[8] and man:rrestore[8] utilities can be used for this purpose, they are not considered to be secure. Instead, one can use `dump` and `restore` in a more secure fashion over an SSH connection. This example creates a full, compressed backup of [.filename]#/usr# and sends the backup file to the specified host over a SSH connection. .Using `dump` over ssh [example] ==== [source,shell] .... # /sbin/dump -0uan -f - /usr | gzip -2 | ssh -c blowfish \ targetuser@targetmachine.example.com dd of=/mybigfiles/dump-usr-l0.gz .... ==== This example sets `RSH` in order to write the backup to a tape drive on a remote system over a SSH connection: .Using `dump` over ssh with `RSH` Set [example] ==== [source,shell] .... # env RSH=/usr/bin/ssh /sbin/dump -0uan -f targetuser@targetmachine.example.com:/dev/sa0 /usr .... ==== === Directory Backups Several built-in utilities are available for backing up and restoring specified files and directories as needed. A good choice for making a backup of all of the files in a directory is man:tar[1]. This utility dates back to Version 6 of AT&T UNIX(R) and by default assumes a recursive backup to a local tape device. Switches can be used to instead specify the name of a backup file. This example creates a compressed backup of the current directory and saves it to [.filename]#/tmp/mybackup.tgz#. When creating a backup file, make sure that the backup is not saved to the same directory that is being backed up. .Backing Up the Current Directory with `tar` [example] ==== [source,shell] .... # tar czvf /tmp/mybackup.tgz . .... ==== To restore the entire backup, `cd` into the directory to restore into and specify the name of the backup. Note that this will overwrite any newer versions of files in the restore directory. When in doubt, restore to a temporary directory or specify the name of the file within the backup to restore. .Restoring Up the Current Directory with `tar` [example] ==== [source,shell] .... # tar xzvf /tmp/mybackup.tgz .... ==== There are dozens of available switches which are described in man:tar[1]. This utility also supports the use of exclude patterns to specify which files should not be included when backing up the specified directory or restoring files from a backup. To create a backup using a specified list of files and directories, man:cpio[1] is a good choice. Unlike `tar`, `cpio` does not know how to walk the directory tree and it must be provided the list of files to backup. For example, a list of files can be created using `ls` or `find`. This example creates a recursive listing of the current directory which is then piped to `cpio` in order to create an output backup file named [.filename]#/tmp/mybackup.cpio#. .Using `ls` and `cpio` to Make a Recursive Backup of the Current Directory [example] ==== [source,shell] .... # ls -R | cpio -ovF /tmp/mybackup.cpio .... ==== A backup utility which tries to bridge the features provided by `tar` and `cpio` is man:pax[1]. Over the years, the various versions of `tar` and `cpio` became slightly incompatible. POSIX(R) created `pax` which attempts to read and write many of the various `cpio` and `tar` formats, plus new formats of its own. The `pax` equivalent to the previous examples would be: .Backing Up the Current Directory with `pax` [example] ==== [source,shell] .... # pax -wf /tmp/mybackup.pax . .... ==== [[backups-tapebackups]] === Using Data Tapes for Backups While tape technology has continued to evolve, modern backup systems tend to combine off-site backups with local removable media. FreeBSD supports any tape drive that uses SCSI, such as LTO or DAT. There is limited support for SATA and USB tape drives. For SCSI tape devices, FreeBSD uses the man:sa[4] driver and the [.filename]#/dev/sa0#, [.filename]#/dev/nsa0#, and [.filename]#/dev/esa0# devices. The physical device name is [.filename]#/dev/sa0#. When [.filename]#/dev/nsa0# is used, the backup application will not rewind the tape after writing a file, which allows writing more than one file to a tape. Using [.filename]#/dev/esa0# ejects the tape after the device is closed. In FreeBSD, `mt` is used to control operations of the tape drive, such as seeking through files on a tape or writing tape control marks to the tape. For example, the first three files on a tape can be preserved by skipping past them before writing a new file: [source,shell] .... # mt -f /dev/nsa0 fsf 3 .... This utility supports many operations. Refer to man:mt[1] for details. To write a single file to tape using `tar`, specify the name of the tape device and the file to backup: [source,shell] .... # tar cvf /dev/sa0 file .... To recover files from a `tar` archive on tape into the current directory: [source,shell] .... # tar xvf /dev/sa0 .... To backup a UFS file system, use `dump`. This examples backs up [.filename]#/usr# without rewinding the tape when finished: [source,shell] .... # dump -0aL -b64 -f /dev/nsa0 /usr .... To interactively restore files from a `dump` file on tape into the current directory: [source,shell] .... # restore -i -f /dev/nsa0 .... [[backups-programs-amanda]] === Third-Party Backup Utilities The FreeBSD Ports Collection provides many third-party utilities which can be used to schedule the creation of backups, simplify tape backup, and make backups easier and more convenient. Many of these applications are client/server based and can be used to automate the backups of a single system or all of the computers in a network. Popular utilities include Amanda, Bacula, rsync, and duplicity. === Emergency Recovery In addition to regular backups, it is recommended to perform the following steps as part of an emergency preparedness plan. Create a print copy of the output of the following commands: * `gpart show` * `more /etc/fstab` * `dmesg` Store this printout and a copy of the installation media in a secure location. Should an emergency restore be needed, boot into the installation media and select `Live CD` to access a rescue shell. This rescue mode can be used to view the current state of the system, and if needed, to reformat disks and restore data from backups. Next, test the rescue shell and the backups. Make notes of the procedure. Store these notes with the media, the printouts, and the backups. These notes may prevent the inadvertent destruction of the backups while under the stress of performing an emergency recovery. For an added measure of security, store the latest backup at a remote location which is physically separated from the computers and disk drives by a significant distance. [[disks-virtual]] == Memory Disks In addition to physical disks, FreeBSD also supports the creation and use of memory disks. One possible use for a memory disk is to access the contents of an ISO file system without the overhead of first burning it to a CD or DVD, then mounting the CD/DVD media. In FreeBSD, the man:md[4] driver is used to provide support for memory disks. The [.filename]#GENERIC# kernel includes this driver. When using a custom kernel configuration file, ensure it includes this line: [.programlisting] .... device md .... [[disks-mdconfig]] === Attaching and Detaching Existing Images To mount an existing file system image, use `mdconfig` to specify the name of the ISO file and a free unit number. Then, refer to that unit number to mount it on an existing mount point. Once mounted, the files in the ISO will appear in the mount point. This example attaches _diskimage.iso_ to the memory device [.filename]#/dev/md0# then mounts that memory device on [.filename]#/mnt#: [source,shell] .... # mdconfig -f diskimage.iso -u 0 # mount -t cd9660 /dev/md0 /mnt .... Notice that `-t cd9660` was used to mount an ISO format. If a unit number is not specified with `-u`, `mdconfig` will automatically allocate an unused memory device and output the name of the allocated unit, such as [.filename]#md4#. Refer to man:mdconfig[8] for more details about this command and its options. When a memory disk is no longer in use, its resources should be released back to the system. First, unmount the file system, then use `mdconfig` to detach the disk from the system and release its resources. To continue this example: [source,shell] .... # umount /mnt # mdconfig -d -u 0 .... To determine if any memory disks are still attached to the system, type `mdconfig -l`. [[disks-md-freebsd5]] === Creating a File- or Memory-Backed Memory Disk FreeBSD also supports memory disks where the storage to use is allocated from either a hard disk or an area of memory. The first method is commonly referred to as a file-backed file system and the second method as a memory-backed file system. Both types can be created using `mdconfig`. To create a new memory-backed file system, specify a type of `swap` and the size of the memory disk to create. Then, format the memory disk with a file system and mount as usual. This example creates a 5M memory disk on unit `1`. That memory disk is then formatted with the UFS file system before it is mounted: [source,shell] .... # mdconfig -a -t swap -s 5m -u 1 # newfs -U md1 /dev/md1: 5.0MB (10240 sectors) block size 16384, fragment size 2048 using 4 cylinder groups of 1.27MB, 81 blks, 192 inodes. with soft updates super-block backups (for fsck -b #) at: 160, 2752, 5344, 7936 # mount /dev/md1 /mnt # df /mnt Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/md1 4718 4 4338 0% /mnt .... To create a new file-backed memory disk, first allocate an area of disk to use. This example creates an empty 5MB file named [.filename]#newimage#: [source,shell] .... # dd if=/dev/zero of=newimage bs=1k count=5k 5120+0 records in 5120+0 records out .... Next, attach that file to a memory disk, label the memory disk and format it with the UFS file system, mount the memory disk, and verify the size of the file-backed disk: [source,shell] .... # mdconfig -f newimage -u 0 # bsdlabel -w md0 auto # newfs -U md0a /dev/md0a: 5.0MB (10224 sectors) block size 16384, fragment size 2048 using 4 cylinder groups of 1.25MB, 80 blks, 192 inodes. super-block backups (for fsck -b #) at: 160, 2720, 5280, 7840 # mount /dev/md0a /mnt # df /mnt Filesystem 1K-blocks Used Avail Capacity Mounted on /dev/md0a 4710 4 4330 0% /mnt .... It takes several commands to create a file- or memory-backed file system using `mdconfig`. FreeBSD also comes with `mdmfs` which automatically configures a memory disk, formats it with the UFS file system, and mounts it. For example, after creating _newimage_ with `dd`, this one command is equivalent to running the `bsdlabel`, `newfs`, and `mount` commands shown above: [source,shell] .... # mdmfs -F newimage -s 5m md0 /mnt .... To instead create a new memory-based memory disk with `mdmfs`, use this one command: [source,shell] .... # mdmfs -s 5m md1 /mnt .... If the unit number is not specified, `mdmfs` will automatically select an unused memory device. For more details about `mdmfs`, refer to man:mdmfs[8]. [[snapshots]] == File System Snapshots FreeBSD offers a feature in conjunction with crossref:config[soft-updates,Soft Updates]: file system snapshots. UFS snapshots allow a user to create images of specified file systems, and treat them as a file. Snapshot files must be created in the file system that the action is performed on, and a user may create no more than 20 snapshots per file system. Active snapshots are recorded in the superblock so they are persistent across unmount and remount operations along with system reboots. When a snapshot is no longer required, it can be removed using man:rm[1]. While snapshots may be removed in any order, all the used space may not be acquired because another snapshot will possibly claim some of the released blocks. The un-alterable `snapshot` file flag is set by man:mksnap_ffs[8] after initial creation of a snapshot file. man:unlink[1] makes an exception for snapshot files since it allows them to be removed. Snapshots are created using man:mount[8]. To place a snapshot of [.filename]#/var# in the file [.filename]#/var/snapshot/snap#, use the following command: [source,shell] .... # mount -u -o snapshot /var/snapshot/snap /var .... Alternatively, use man:mksnap_ffs[8] to create the snapshot: [source,shell] .... # mksnap_ffs /var /var/snapshot/snap .... One can find snapshot files on a file system, such as [.filename]#/var#, using man:find[1]: [source,shell] .... # find /var -flags snapshot .... Once a snapshot has been created, it has several uses: * Some administrators will use a snapshot file for backup purposes, because the snapshot can be transferred to CDs or tape. * The file system integrity checker, man:fsck[8], may be run on the snapshot. Assuming that the file system was clean when it was mounted, this should always provide a clean and unchanging result. * Running man:dump[8] on the snapshot will produce a dump file that is consistent with the file system and the timestamp of the snapshot. man:dump[8] can also take a snapshot, create a dump image, and then remove the snapshot in one command by using `-L`. * The snapshot can be mounted as a frozen image of the file system. To man:mount[8] the snapshot [.filename]#/var/snapshot/snap# run: + [source,shell] .... # mdconfig -a -t vnode -o readonly -f /var/snapshot/snap -u 4 # mount -r /dev/md4 /mnt .... The frozen [.filename]#/var# is now available through [.filename]#/mnt#. Everything will initially be in the same state it was during the snapshot creation time. The only exception is that any earlier snapshots will appear as zero length files. To unmount the snapshot, use: [source,shell] .... # umount /mnt # mdconfig -d -u 4 .... For more information about `softupdates` and file system snapshots, including technical papers, visit Marshall Kirk McKusick's website at http://www.mckusick.com/[http://www.mckusick.com/]. [[quotas]] == Disk Quotas Disk quotas can be used to limit the amount of disk space or the number of files a user or members of a group may allocate on a per-file system basis. This prevents one user or group of users from consuming all of the available disk space. This section describes how to configure disk quotas for the UFS file system. To configure quotas on the ZFS file system, refer to crossref:zfs[zfs-zfs-quota,"Dataset, User, and Group Quotas"] === Enabling Disk Quotas To determine if the FreeBSD kernel provides support for disk quotas: [source,shell] .... % sysctl kern.features.ufs_quota kern.features.ufs_quota: 1 .... In this example, the `1` indicates quota support. If the value is instead `0`, add the following line to a custom kernel configuration file and rebuild the kernel using the instructions in crossref:kernelconfig[kernelconfig,Configuring the FreeBSD Kernel]: [.programlisting] .... options QUOTA .... Next, enable disk quotas in [.filename]#/etc/rc.conf#: [.programlisting] .... quota_enable="YES" .... Normally on bootup, the quota integrity of each file system is checked by man:quotacheck[8]. This program insures that the data in the quota database properly reflects the data on the file system. This is a time consuming process that will significantly affect the time the system takes to boot. To skip this step, add this variable to [.filename]#/etc/rc.conf#: [.programlisting] .... check_quotas="NO" .... Finally, edit [.filename]#/etc/fstab# to enable disk quotas on a per-file system basis. To enable per-user quotas on a file system, add `userquota` to the options field in the [.filename]#/etc/fstab# entry for the file system to enable quotas on. For example: [.programlisting] .... /dev/da1s2g /home ufs rw,userquota 1 2 .... To enable group quotas, use `groupquota` instead. To enable both user and group quotas, separate the options with a comma: [.programlisting] .... /dev/da1s2g /home ufs rw,userquota,groupquota 1 2 .... By default, quota files are stored in the root directory of the file system as [.filename]#quota.user# and [.filename]#quota.group#. Refer to man:fstab[5] for more information. Specifying an alternate location for the quota files is not recommended. Once the configuration is complete, reboot the system and [.filename]#/etc/rc# will automatically run the appropriate commands to create the initial quota files for all of the quotas enabled in [.filename]#/etc/fstab#. In the normal course of operations, there should be no need to manually run man:quotacheck[8], man:quotaon[8], or man:quotaoff[8]. However, one should read these manual pages to be familiar with their operation. === Setting Quota Limits To verify that quotas are enabled, run: [source,shell] .... # quota -v .... There should be a one line summary of disk usage and current quota limits for each file system that quotas are enabled on. The system is now ready to be assigned quota limits with `edquota`. Several options are available to enforce limits on the amount of disk space a user or group may allocate, and how many files they may create. Allocations can be limited based on disk space (block quotas), number of files (inode quotas), or a combination of both. Each limit is further broken down into two categories: hard and soft limits. A hard limit may not be exceeded. Once a user reaches a hard limit, no further allocations can be made on that file system by that user. For example, if the user has a hard limit of 500 kbytes on a file system and is currently using 490 kbytes, the user can only allocate an additional 10 kbytes. Attempting to allocate an additional 11 kbytes will fail. Soft limits can be exceeded for a limited amount of time, known as the grace period, which is one week by default. If a user stays over their limit longer than the grace period, the soft limit turns into a hard limit and no further allocations are allowed. When the user drops back below the soft limit, the grace period is reset. In the following example, the quota for the `test` account is being edited. When `edquota` is invoked, the editor specified by `EDITOR` is opened in order to edit the quota limits. The default editor is set to vi. [source,shell] .... # edquota -u test Quotas for user test: /usr: kbytes in use: 65, limits (soft = 50, hard = 75) inodes in use: 7, limits (soft = 50, hard = 60) /usr/var: kbytes in use: 0, limits (soft = 50, hard = 75) inodes in use: 0, limits (soft = 50, hard = 60) .... There are normally two lines for each file system that has quotas enabled. One line represents the block limits and the other represents the inode limits. Change the value to modify the quota limit. For example, to raise the block limit on [.filename]#/usr# to a soft limit of `500` and a hard limit of `600`, change the values in that line as follows: [.programlisting] .... /usr: kbytes in use: 65, limits (soft = 500, hard = 600) .... The new quota limits take effect upon exiting the editor. Sometimes it is desirable to set quota limits on a range of users. This can be done by first assigning the desired quota limit to a user. Then, use `-p` to duplicate that quota to a specified range of user IDs (UIDs). The following command will duplicate those quota limits for UIDs `10,000` through `19,999`: [source,shell] .... # edquota -p test 10000-19999 .... For more information, refer to man:edquota[8]. === Checking Quota Limits and Disk Usage To check individual user or group quotas and disk usage, use man:quota[1]. A user may only examine their own quota and the quota of a group they are a member of. Only the superuser may view all user and group quotas. To get a summary of all quotas and disk usage for file systems with quotas enabled, use man:repquota[8]. Normally, file systems that the user is not using any disk space on will not show in the output of `quota`, even if the user has a quota limit assigned for that file system. Use `-v` to display those file systems. The following is sample output from `quota -v` for a user that has quota limits on two file systems. [.programlisting] .... Disk quotas for user test (uid 1002): Filesystem usage quota limit grace files quota limit grace /usr 65* 50 75 5days 7 50 60 /usr/var 0 50 75 0 50 60 .... In this example, the user is currently 15 kbytes over the soft limit of 50 kbytes on [.filename]#/usr# and has 5 days of grace period left. The asterisk `*` indicates that the user is currently over the quota limit. === Quotas over NFS Quotas are enforced by the quota subsystem on the NFS server. The man:rpc.rquotad[8] daemon makes quota information available to `quota` on NFS clients, allowing users on those machines to see their quota statistics. On the NFS server, enable `rpc.rquotad` by removing the `+#+` from this line in [.filename]*/etc/inetd.conf*: [.programlisting] .... rquotad/1 dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad .... Then, restart `inetd`: [source,shell] .... # service inetd restart .... [[disks-encrypting]] == Encrypting Disk Partitions FreeBSD offers excellent online protections against unauthorized data access. File permissions and crossref:mac[mac,Mandatory Access Control] (MAC) help prevent unauthorized users from accessing data while the operating system is active and the computer is powered up. However, the permissions enforced by the operating system are irrelevant if an attacker has physical access to a computer and can move the computer's hard drive to another system to copy and analyze the data. Regardless of how an attacker may have come into possession of a hard drive or powered-down computer, the GEOM-based cryptographic subsystems built into FreeBSD are able to protect the data on the computer's file systems against even highly-motivated attackers with significant resources. Unlike encryption methods that encrypt individual files, the built-in `gbde` and `geli` utilities can be used to transparently encrypt entire file systems. No cleartext ever touches the hard drive's platter. This chapter demonstrates how to create an encrypted file system on FreeBSD. It first demonstrates the process using `gbde` and then demonstrates the same example using `geli`. === Disk Encryption with gbde The objective of the man:gbde[4] facility is to provide a formidable challenge for an attacker to gain access to the contents of a _cold_ storage device. However, if the computer is compromised while up and running and the storage device is actively attached, or the attacker has access to a valid passphrase, it offers no protection to the contents of the storage device. Thus, it is important to provide physical security while the system is running and to protect the passphrase used by the encryption mechanism. This facility provides several barriers to protect the data stored in each disk sector. It encrypts the contents of a disk sector using 128-bit AES in CBC mode. Each sector on the disk is encrypted with a different AES key. For more information on the cryptographic design, including how the sector keys are derived from the user-supplied passphrase, refer to man:gbde[4]. FreeBSD provides a kernel module for gbde which can be loaded with this command: [source,shell] .... # kldload geom_bde .... If using a custom kernel configuration file, ensure it contains this line: `options GEOM_BDE` The following example demonstrates adding a new hard drive to a system that will hold a single encrypted partition that will be mounted as [.filename]#/private#. [.procedure] .Procedure: Encrypting a Partition with gbde . Add the New Hard Drive + Install the new drive to the system as explained in <>. For the purposes of this example, a new hard drive partition has been added as [.filename]#/dev/ad4s1c# and [.filename]#/dev/ad0s1*# represents the existing standard FreeBSD partitions. + [source,shell] .... # ls /dev/ad* /dev/ad0 /dev/ad0s1b /dev/ad0s1e /dev/ad4s1 /dev/ad0s1 /dev/ad0s1c /dev/ad0s1f /dev/ad4s1c /dev/ad0s1a /dev/ad0s1d /dev/ad4 .... . Create a Directory to Hold `gbde` Lock Files + [source,shell] .... # mkdir /etc/gbde .... + The gbde lock file contains information that gbde requires to access encrypted partitions. Without access to the lock file, gbde will not be able to decrypt the data contained in the encrypted partition without significant manual intervention which is not supported by the software. Each encrypted partition uses a separate lock file. . Initialize the `gbde` Partition + A gbde partition must be initialized before it can be used. This initialization needs to be performed only once. This command will open the default editor, in order to set various configuration options in a template. For use with the UFS file system, set the sector_size to 2048: + [source,shell] .... # gbde init /dev/ad4s1c -i -L /etc/gbde/ad4s1c.lock -# $FreeBSD: src/sbin/gbde/template.txt,v 1.1.36.1 2009/08/03 08:13:06 kensmith Exp $ # # Sector size is the smallest unit of data which can be read or written. # Making it too small decreases performance and decreases available space. # Making it too large may prevent filesystems from working. 512 is the # minimum and always safe. For UFS, use the fragment size # sector_size = 2048 [...] .... + Once the edit is saved, the user will be asked twice to type the passphrase used to secure the data. The passphrase must be the same both times. The ability of gbde to protect data depends entirely on the quality of the passphrase. For tips on how to select a secure passphrase that is easy to remember, see http://world.std.com/\~reinhold/diceware.html[http://world.std.com/~reinhold/diceware.htm]. + This initialization creates a lock file for the gbde partition. In this example, it is stored as [.filename]#/etc/gbde/ad4s1c.lock#. Lock files must end in ".lock" in order to be correctly detected by the [.filename]#/etc/rc.d/gbde# start up script. + [CAUTION] ==== Lock files _must_ be backed up together with the contents of any encrypted partitions. Without the lock file, the legitimate owner will be unable to access the data on the encrypted partition. ==== . Attach the Encrypted Partition to the Kernel + [source,shell] .... # gbde attach /dev/ad4s1c -l /etc/gbde/ad4s1c.lock .... + This command will prompt to input the passphrase that was selected during the initialization of the encrypted partition. The new encrypted device will appear in [.filename]#/dev# as [.filename]#/dev/device_name.bde#: + [source,shell] .... # ls /dev/ad* /dev/ad0 /dev/ad0s1b /dev/ad0s1e /dev/ad4s1 /dev/ad0s1 /dev/ad0s1c /dev/ad0s1f /dev/ad4s1c /dev/ad0s1a /dev/ad0s1d /dev/ad4 /dev/ad4s1c.bde .... . Create a File System on the Encrypted Device + Once the encrypted device has been attached to the kernel, a file system can be created on the device. This example creates a UFS file system with soft updates enabled. Be sure to specify the partition which has a [.filename]#*.bde# extension: + [source,shell] .... # newfs -U /dev/ad4s1c.bde .... . Mount the Encrypted Partition + Create a mount point and mount the encrypted file system: + [source,shell] .... # mkdir /private # mount /dev/ad4s1c.bde /private .... . Verify That the Encrypted File System is Available + The encrypted file system should now be visible and available for use: + [source,shell] .... % df -H Filesystem Size Used Avail Capacity Mounted on /dev/ad0s1a 1037M 72M 883M 8% / /devfs 1.0K 1.0K 0B 100% /dev /dev/ad0s1f 8.1G 55K 7.5G 0% /home /dev/ad0s1e 1037M 1.1M 953M 0% /tmp /dev/ad0s1d 6.1G 1.9G 3.7G 35% /usr /dev/ad4s1c.bde 150G 4.1K 138G 0% /private .... After each boot, any encrypted file systems must be manually re-attached to the kernel, checked for errors, and mounted, before the file systems can be used. To configure these steps, add the following lines to [.filename]#/etc/rc.conf#: [.programlisting] .... gbde_autoattach_all="YES" gbde_devices="ad4s1c" gbde_lockdir="/etc/gbde" .... This requires that the passphrase be entered at the console at boot time. After typing the correct passphrase, the encrypted partition will be mounted automatically. Additional gbde boot options are available and listed in man:rc.conf[5]. [NOTE] ==== sysinstall is incompatible with gbde-encrypted devices. All [.filename]#*.bde# devices must be detached from the kernel before starting sysinstall or it will crash during its initial probing for devices. To detach the encrypted device used in the example, use the following command: [source,shell] .... # gbde detach /dev/ad4s1c .... ==== [[disks-encrypting-geli]] === Disk Encryption with `geli` An alternative cryptographic GEOM class is available using `geli`. This control utility adds some features and uses a different scheme for doing cryptographic work. It provides the following features: * Utilizes the man:crypto[9] framework and automatically uses cryptographic hardware when it is available. * Supports multiple cryptographic algorithms such as AES-XTS, AES-CBC, and Camellia-CBCAES. * Allows the root partition to be encrypted. The passphrase used to access the encrypted root partition will be requested during system boot. * Allows the use of two independent keys. * It is fast as it performs simple sector-to-sector encryption. * Allows backup and restore of master keys. If a user destroys their keys, it is still possible to get access to the data by restoring keys from the backup. * Allows a disk to attach with a random, one-time key which is useful for swap partitions and temporary file systems. More features and usage examples can be found in man:geli[8]. The following example describes how to generate a key file which will be used as part of the master key for the encrypted provider mounted under [.filename]#/private#. The key file will provide some random data used to encrypt the master key. The master key will also be protected by a passphrase. The provider's sector size will be 4kB. The example describes how to attach to the `geli` provider, create a file system on it, mount it, work with it, and finally, how to detach it. [.procedure] .Procedure: Encrypting a Partition with `geli` . Load `geli` Support + Support for `geli` is available as a loadable kernel module. To configure the system to automatically load the module at boot time, add the following line to [.filename]#/boot/loader.conf#: + [.programlisting] .... geom_eli_load="YES" .... + To load the kernel module now: + [source,shell] .... # kldload geom_eli .... + For a custom kernel, ensure the kernel configuration file contains these lines: + [.programlisting] .... options GEOM_ELI device crypto .... . Generate the Master Key + The following commands generate a master key that all data will be encrypted with. This key can never be changed. Rather than using it directly, it is encrypted with one or more user keys. The user keys are made up of an optional combination of random bytes from a file, [.filename]#/root/da2.key#, and/or a passphrase. In this case, the data source for the key file is [.filename]#/dev/random#. This command also configures the sector size of the provider ([.filename]#/dev/da2.eli#) as 4kB, for better performance: + [source,shell] .... # dd if=/dev/random of=/root/da2.key bs=64 count=1 # geli init -K /root/da2.key -s 4096 /dev/da2 Enter new passphrase: Reenter new passphrase: .... + It is not mandatory to use both a passphrase and a key file as either method of securing the master key can be used in isolation. + If the key file is given as "-", standard input will be used. For example, this command generates three key files: + [source,shell] .... # cat keyfile1 keyfile2 keyfile3 | geli init -K - /dev/da2 .... . Attach the Provider with the Generated Key + To attach the provider, specify the key file, the name of the disk, and the passphrase: + [source,shell] .... # geli attach -k /root/da2.key /dev/da2 Enter passphrase: .... + This creates a new device with an [.filename]#.eli# extension: + [source,shell] .... # ls /dev/da2* /dev/da2 /dev/da2.eli .... . Create the New File System + Next, format the device with the UFS file system and mount it on an existing mount point: + [source,shell] .... # dd if=/dev/random of=/dev/da2.eli bs=1m # newfs /dev/da2.eli # mount /dev/da2.eli /private .... + The encrypted file system should now be available for use: + [source,shell] .... # df -H Filesystem Size Used Avail Capacity Mounted on /dev/ad0s1a 248M 89M 139M 38% / /devfs 1.0K 1.0K 0B 100% /dev /dev/ad0s1f 7.7G 2.3G 4.9G 32% /usr /dev/ad0s1d 989M 1.5M 909M 0% /tmp /dev/ad0s1e 3.9G 1.3G 2.3G 35% /var /dev/da2.eli 150G 4.1K 138G 0% /private .... Once the work on the encrypted partition is done, and the [.filename]#/private# partition is no longer needed, it is prudent to put the device into cold storage by unmounting and detaching the `geli` encrypted partition from the kernel: [source,shell] .... # umount /private # geli detach da2.eli .... An [.filename]#rc.d# script is provided to simplify the mounting of `geli`-encrypted devices at boot time. For this example, add these lines to [.filename]#/etc/rc.conf#: [.programlisting] .... geli_devices="da2" geli_da2_flags="-k /root/da2.key" .... This configures [.filename]#/dev/da2# as a `geli` provider with a master key of [.filename]#/root/da2.key#. The system will automatically detach the provider from the kernel before the system shuts down. During the startup process, the script will prompt for the passphrase before attaching the provider. Other kernel messages might be shown before and after the password prompt. If the boot process seems to stall, look carefully for the password prompt among the other messages. Once the correct passphrase is entered, the provider is attached. The file system is then mounted, typically by an entry in [.filename]#/etc/fstab#. Refer to crossref:basics[mount-unmount,“Mounting and Unmounting File Systems”] for instructions on how to configure a file system to mount at boot time. [[swap-encrypting]] == Encrypting Swap Like the encryption of disk partitions, encryption of swap space is used to protect sensitive information. Consider an application that deals with passwords. As long as these passwords stay in physical memory, they are not written to disk and will be cleared after a reboot. However, if FreeBSD starts swapping out memory pages to free space, the passwords may be written to the disk unencrypted. Encrypting swap space can be a solution for this scenario. This section demonstrates how to configure an encrypted swap partition using man:gbde[8] or man:geli[8] encryption. It assumes that [.filename]#/dev/ada0s1b# is the swap partition. === Configuring Encrypted Swap Swap partitions are not encrypted by default and should be cleared of any sensitive data before continuing. To overwrite the current swap partition with random garbage, execute the following command: [source,shell] .... # dd if=/dev/random of=/dev/ada0s1b bs=1m .... To encrypt the swap partition using man:gbde[8], add the `.bde` suffix to the swap line in [.filename]#/etc/fstab#: [.programlisting] .... # Device Mountpoint FStype Options Dump Pass# /dev/ada0s1b.bde none swap sw 0 0 .... To instead encrypt the swap partition using man:geli[8], use the `.eli` suffix: [.programlisting] .... # Device Mountpoint FStype Options Dump Pass# /dev/ada0s1b.eli none swap sw 0 0 .... By default, man:geli[8] uses the AES algorithm with a key length of 128 bits. Normally the default settings will suffice. If desired, these defaults can be altered in the options field in [.filename]#/etc/fstab#. The possible flags are: aalgo:: Data integrity verification algorithm used to ensure that the encrypted data has not been tampered with. See man:geli[8] for a list of supported algorithms. ealgo:: Encryption algorithm used to protect the data. See man:geli[8] for a list of supported algorithms. keylen:: The length of the key used for the encryption algorithm. See man:geli[8] for the key lengths that are supported by each encryption algorithm. sectorsize:: The size of the blocks data is broken into before it is encrypted. Larger sector sizes increase performance at the cost of higher storage overhead. The recommended size is 4096 bytes. This example configures an encrypted swap partition using the AES-XTS algorithm with a key length of 128 bits and a sectorsize of 4 kilobytes: [.programlisting] .... # Device Mountpoint FStype Options Dump Pass# /dev/ada0s1b.eli none swap sw,ealgo=AES-XTS,keylen=128,sectorsize=4096 0 0 .... === Encrypted Swap Verification Once the system has rebooted, proper operation of the encrypted swap can be verified using `swapinfo`. If man:gbde[8] is being used: [source,shell] .... % swapinfo Device 1K-blocks Used Avail Capacity /dev/ada0s1b.bde 542720 0 542720 0 .... If man:geli[8] is being used: [source,shell] .... % swapinfo Device 1K-blocks Used Avail Capacity /dev/ada0s1b.eli 542720 0 542720 0 .... [[disks-hast]] == Highly Available Storage (HAST) High availability is one of the main requirements in serious business applications and highly-available storage is a key component in such environments. In FreeBSD, the Highly Available STorage (HAST) framework allows transparent storage of the same data across several physically separated machines connected by a TCP/IP network. HAST can be understood as a network-based RAID1 (mirror), and is similar to the DRBD(R) storage system used in the GNU/Linux(R) platform. In combination with other high-availability features of FreeBSD like CARP, HAST makes it possible to build a highly-available storage cluster that is resistant to hardware failures. The following are the main features of HAST: * Can be used to mask I/O errors on local hard drives. * File system agnostic as it works with any file system supported by FreeBSD. * Efficient and quick resynchronization as only the blocks that were modified during the downtime of a node are synchronized. * Can be used in an already deployed environment to add additional redundancy. * Together with CARP, Heartbeat, or other tools, it can be used to build a robust and durable storage system. After reading this section, you will know: * What HAST is, how it works, and which features it provides. * How to set up and use HAST on FreeBSD. * How to integrate CARP and man:devd[8] to build a robust storage system. Before reading this section, you should: * Understand UNIX(R) and FreeBSD basics (crossref:basics[basics,FreeBSD Basics]). * Know how to configure network interfaces and other core FreeBSD subsystems (crossref:config[config-tuning,Configuration and Tuning]). * Have a good understanding of FreeBSD networking (crossref:partiv[network-communication,"Network Communication"]). The HAST project was sponsored by The FreeBSD Foundation with support from http://www.omc.net/[http://www.omc.net/] and http://www.transip.nl/[http://www.transip.nl/]. === HAST Operation HAST provides synchronous block-level replication between two physical machines: the _primary_ node and the _secondary_ node. These two machines together are referred to as a cluster. Since HAST works in a primary-secondary configuration, it allows only one of the cluster nodes to be active at any given time. The primary node, also called _active_, is the one which will handle all the I/O requests to HAST-managed devices. The secondary node is automatically synchronized from the primary node. The physical components of the HAST system are the local disk on primary node, and the disk on the remote, secondary node. HAST operates synchronously on a block level, making it transparent to file systems and applications. HAST provides regular GEOM providers in [.filename]#/dev/hast/# for use by other tools or applications. There is no difference between using HAST-provided devices and raw disks or partitions. Each write, delete, or flush operation is sent to both the local disk and to the remote disk over TCP/IP. Each read operation is served from the local disk, unless the local disk is not up-to-date or an I/O error occurs. In such cases, the read operation is sent to the secondary node. HAST tries to provide fast failure recovery. For this reason, it is important to reduce synchronization time after a node's outage. To provide fast synchronization, HAST manages an on-disk bitmap of dirty extents and only synchronizes those during a regular synchronization, with an exception of the initial sync. There are many ways to handle synchronization. HAST implements several replication modes to handle different synchronization methods: * _memsync_: This mode reports a write operation as completed when the local write operation is finished and when the remote node acknowledges data arrival, but before actually storing the data. The data on the remote node will be stored directly after sending the acknowledgement. This mode is intended to reduce latency, but still provides good reliability. This mode is the default. * _fullsync_: This mode reports a write operation as completed when both the local write and the remote write complete. This is the safest and the slowest replication mode. * _async_: This mode reports a write operation as completed when the local write completes. This is the fastest and the most dangerous replication mode. It should only be used when replicating to a distant node where latency is too high for other modes. === HAST Configuration The HAST framework consists of several components: * The man:hastd[8] daemon which provides data synchronization. When this daemon is started, it will automatically load `geom_gate.ko`. * The userland management utility, man:hastctl[8]. * The man:hast.conf[5] configuration file. This file must exist before starting hastd. Users who prefer to statically build `GEOM_GATE` support into the kernel should add this line to the custom kernel configuration file, then rebuild the kernel using the instructions in crossref:kernelconfig[kernelconfig,Configuring the FreeBSD Kernel]: [.programlisting] .... options GEOM_GATE .... The following example describes how to configure two nodes in primary-secondary operation using HAST to replicate the data between the two. The nodes will be called `hasta`, with an IP address of `172.16.0.1`, and `hastb`, with an IP address of `172.16.0.2`. Both nodes will have a dedicated hard drive [.filename]#/dev/ad6# of the same size for HAST operation. The HAST pool, sometimes referred to as a resource or the GEOM provider in [.filename]#/dev/hast/#, will be called `test`. Configuration of HAST is done using [.filename]#/etc/hast.conf#. This file should be identical on both nodes. The simplest configuration is: [.programlisting] .... resource test { on hasta { local /dev/ad6 remote 172.16.0.2 } on hastb { local /dev/ad6 remote 172.16.0.1 } } .... For more advanced configuration, refer to man:hast.conf[5]. [TIP] ==== It is also possible to use host names in the `remote` statements if the hosts are resolvable and defined either in [.filename]#/etc/hosts# or in the local DNS. ==== Once the configuration exists on both nodes, the HAST pool can be created. Run these commands on both nodes to place the initial metadata onto the local disk and to start man:hastd[8]: [source,shell] .... # hastctl create test # service hastd onestart .... [NOTE] ==== It is _not_ possible to use GEOM providers with an existing file system or to convert an existing storage to a HAST-managed pool. This procedure needs to store some metadata on the provider and there will not be enough required space available on an existing provider. ==== A HAST node's `primary` or `secondary` role is selected by an administrator, or software like Heartbeat, using man:hastctl[8]. On the primary node, `hasta`, issue this command: [source,shell] .... # hastctl role primary test .... Run this command on the secondary node, `hastb`: [source,shell] .... # hastctl role secondary test .... Verify the result by running `hastctl` on each node: [source,shell] .... # hastctl status test .... Check the `status` line in the output. If it says `degraded`, something is wrong with the configuration file. It should say `complete` on each node, meaning that the synchronization between the nodes has started. The synchronization completes when `hastctl status` reports 0 bytes of `dirty` extents. The next step is to create a file system on the GEOM provider and mount it. This must be done on the `primary` node. Creating the file system can take a few minutes, depending on the size of the hard drive. This example creates a UFS file system on [.filename]#/dev/hast/test#: [source,shell] .... # newfs -U /dev/hast/test # mkdir /hast/test # mount /dev/hast/test /hast/test .... Once the HAST framework is configured properly, the final step is to make sure that HAST is started automatically during system boot. Add this line to [.filename]#/etc/rc.conf#: [.programlisting] .... hastd_enable="YES" .... ==== Failover Configuration The goal of this example is to build a robust storage system which is resistant to the failure of any given node. If the primary node fails, the secondary node is there to take over seamlessly, check and mount the file system, and continue to work without missing a single bit of data. To accomplish this task, the Common Address Redundancy Protocol (CARP) is used to provide for automatic failover at the IP layer. CARP allows multiple hosts on the same network segment to share an IP address. Set up CARP on both nodes of the cluster according to the documentation available in crossref:advanced-networking[carp,“Common Address Redundancy Protocol (CARP)”]. In this example, each node will have its own management IP address and a shared IP address of _172.16.0.254_. The primary HAST node of the cluster must be the primary CARP node. The HAST pool created in the previous section is now ready to be exported to the other hosts on the network. This can be accomplished by exporting it through NFS or Samba, using the shared IP address _172.16.0.254_. The only problem which remains unresolved is an automatic failover should the primary node fail. In the event of CARP interfaces going up or down, the FreeBSD operating system generates a man:devd[8] event, making it possible to watch for state changes on the CARP interfaces. A state change on the CARP interface is an indication that one of the nodes failed or came back online. These state change events make it possible to run a script which will automatically handle the HAST failover. To catch state changes on the CARP interfaces, add this configuration to [.filename]#/etc/devd.conf# on each node: [.programlisting] .... notify 30 { match "system" "IFNET"; match "subsystem" "carp0"; match "type" "LINK_UP"; action "/usr/local/sbin/carp-hast-switch primary"; }; notify 30 { match "system" "IFNET"; match "subsystem" "carp0"; match "type" "LINK_DOWN"; action "/usr/local/sbin/carp-hast-switch secondary"; }; .... [NOTE] ==== If the systems are running FreeBSD 10 or higher, replace [.filename]#carp0# with the name of the CARP-configured interface. ==== Restart man:devd[8] on both nodes to put the new configuration into effect: [source,shell] .... # service devd restart .... When the specified interface state changes by going up or down , the system generates a notification, allowing the man:devd[8] subsystem to run the specified automatic failover script, [.filename]#/usr/local/sbin/carp-hast-switch#. For further clarification about this configuration, refer to man:devd.conf[5]. Here is an example of an automated failover script: [.programlisting] .... #!/bin/sh # Original script by Freddie Cash # Modified by Michael W. Lucas # and Viktor Petersson # The names of the HAST resources, as listed in /etc/hast.conf resources="test" # delay in mounting HAST resource after becoming primary # make your best guess delay=3 # logging log="local0.debug" name="carp-hast" # end of user configurable stuff case "$1" in primary) logger -p $log -t $name "Switching to primary provider for ${resources}." sleep ${delay} # Wait for any "hastd secondary" processes to stop for disk in ${resources}; do while $( pgrep -lf "hastd: ${disk} \(secondary\)" > /dev/null 2>&1 ); do sleep 1 done # Switch role for each disk hastctl role primary ${disk} if [ $? -ne 0 ]; then logger -p $log -t $name "Unable to change role to primary for resource ${disk}." exit 1 fi done # Wait for the /dev/hast/* devices to appear for disk in ${resources}; do for I in $( jot 60 ); do [ -c "/dev/hast/${disk}" ] && break sleep 0.5 done if [ ! -c "/dev/hast/${disk}" ]; then logger -p $log -t $name "GEOM provider /dev/hast/${disk} did not appear." exit 1 fi done logger -p $log -t $name "Role for HAST resources ${resources} switched to primary." logger -p $log -t $name "Mounting disks." for disk in ${resources}; do mkdir -p /hast/${disk} fsck -p -y -t ufs /dev/hast/${disk} mount /dev/hast/${disk} /hast/${disk} done ;; secondary) logger -p $log -t $name "Switching to secondary provider for ${resources}." # Switch roles for the HAST resources for disk in ${resources}; do if ! mount | grep -q "^/dev/hast/${disk} on " then else umount -f /hast/${disk} fi sleep $delay hastctl role secondary ${disk} 2>&1 if [ $? -ne 0 ]; then logger -p $log -t $name "Unable to switch role to secondary for resource ${disk}." exit 1 fi logger -p $log -t $name "Role switched to secondary for resource ${disk}." done ;; esac .... In a nutshell, the script takes these actions when a node becomes primary: * Promotes the HAST pool to primary on the other node. * Checks the file system under the HAST pool. * Mounts the pool. When a node becomes secondary: * Unmounts the HAST pool. * Degrades the HAST pool to secondary. [CAUTION] ==== This is just an example script which serves as a proof of concept. It does not handle all the possible scenarios and can be extended or altered in any way, for example, to start or stop required services. ==== [TIP] ==== For this example, a standard UFS file system was used. To reduce the time needed for recovery, a journal-enabled UFS or ZFS file system can be used instead. ==== More detailed information with additional examples can be found at http://wiki.FreeBSD.org/HAST[http://wiki.FreeBSD.org/HAST]. === Troubleshooting HAST should generally work without issues. However, as with any other software product, there may be times when it does not work as supposed. The sources of the problems may be different, but the rule of thumb is to ensure that the time is synchronized between the nodes of the cluster. When troubleshooting HAST, the debugging level of man:hastd[8] should be increased by starting `hastd` with `-d`. This argument may be specified multiple times to further increase the debugging level. Consider also using `-F`, which starts `hastd` in the foreground. [[disks-hast-sb]] ==== Recovering from the Split-brain Condition _Split-brain_ occurs when the nodes of the cluster are unable to communicate with each other, and both are configured as primary. This is a dangerous condition because it allows both nodes to make incompatible changes to the data. This problem must be corrected manually by the system administrator. The administrator must either decide which node has more important changes, or perform the merge manually. Then, let HAST perform full synchronization of the node which has the broken data. To do this, issue these commands on the node which needs to be resynchronized: [source,shell] .... # hastctl role init test # hastctl create test # hastctl role secondary test .... diff --git a/documentation/content/en/books/handbook/mail/_index.adoc b/documentation/content/en/books/handbook/mail/_index.adoc index 711ab931da..91d0ee0c7f 100644 --- a/documentation/content/en/books/handbook/mail/_index.adoc +++ b/documentation/content/en/books/handbook/mail/_index.adoc @@ -1,964 +1,962 @@ --- title: Chapter 31. Electronic Mail part: IV. Network Communication prev: books/handbook/ppp-and-slip next: books/handbook/network-servers description: This chapter provides a basic introduction to running a mail server on FreeBSD, as well as an introduction to sending and receiving email using FreeBSD tags: ["mail", "sendmail", "dma", "MTA", "SMTP", "mail user agents", "fetchmail", "procmail", "alpine", "mutt", "postfix"] showBookMenu: true weight: 36 path: "/books/handbook/" --- [[mail]] = Electronic Mail :doctype: book :toc: macro :toclevels: 1 :icons: font :sectnums: :sectnumlevels: 6 :sectnumoffset: 31 :partnums: :source-highlighter: rouge :experimental: :images-path: books/handbook/mail/ ifdef::env-beastie[] ifdef::backend-html5[] :imagesdir: ../../../../images/{images-path} endif::[] ifndef::book[] include::shared/authors.adoc[] include::shared/mirrors.adoc[] include::shared/releases.adoc[] include::shared/attributes/attributes-{{% lang %}}.adoc[] include::shared/{{% lang %}}/teams.adoc[] include::shared/{{% lang %}}/mailing-lists.adoc[] include::shared/{{% lang %}}/urls.adoc[] toc::[] endif::[] ifdef::backend-pdf,backend-epub3[] include::../../../../../shared/asciidoctor.adoc[] endif::[] endif::[] ifndef::env-beastie[] toc::[] include::../../../../../shared/asciidoctor.adoc[] endif::[] [[mail-synopsis]] == Synopsis "Electronic Mail", better known as email, is one of the most widely used forms of communication today. This chapter provides a basic introduction to running a mail server on FreeBSD, as well as an introduction to sending and receiving email using FreeBSD. For a complete coverage of this subject, refer to the books listed in crossref:bibliography[bibliography,Bibliography]. This chapter covers: * Which software components are involved in sending and receiving electronic mail. * How to configure DragonFly Mail Agent. * Where basic Sendmail configuration files are located in FreeBSD. * The difference between remote and local mailboxes. * How to install and configure an alternate Mail Transfer Agent, replacing DragonFly Mail Agent or Sendmail. * How to troubleshoot common mail server problems. * How to configure Sendmail to only send mail. * How to configure SMTP authentication for added security in Sendmail. * How to install and use a Mail User Agent, such as mutt, to send and receive email. * How to download mail from a remote POP or IMAP server. * How to automatically apply filters and rules to incoming email. [[mail-using]] == Mail Components There are five major parts involved in an email exchange: the Mail User Agent (MUA), the Mail Transfer Agent (MTA), a mail host, a remote or local mailbox, and DNS. This section provides an overview of these components. Mail User Agent (MUA):: The Mail User Agent (MUA) is an application which is used to compose, send, and receive emails. This application can be a command line program, such as the built-in `mail` utility or a third-party application from the Ports Collection, such as alpine, elm, or mutt. Dozens of graphical programs are also available in the Ports Collection, including Claws Mail, Evolution, and Thunderbird. Some organizations provide a web mail program which can be accessed through a web browser. More information about installing and using a MUA on FreeBSD can be found in <>. Mail Transfer Agent (MTA):: The Mail Transfer Agent (MTA) is responsible for receiving incoming mail and delivering outgoing mail. Starting with FreeBSD version 14.0, the default MTA is DragonFly Mail Agent (man:dma[8]); in earlier versions, it is man:sendmail[8]. Other MTAs, including Exim, Postfix, and qmail, may be installed to replace the default MTA. Mail Host and Mailboxes:: The mail host is a server that is responsible for delivering and receiving mail for a host or a network. The mail host collects all mail sent to the domain and stores it either in the default `mbox` or the alternative Maildir format, depending on the configuration. Once mail has been stored, it may either be read locally using a MUA or remotely accessed and collected using protocols such as POP or IMAP. If mail is read locally, a POP or IMAP server does not need to be installed. Domain Name System (DNS):: The Domain Name System (DNS) and its daemon man:named[8] play a large role in the delivery of mail. In order to deliver mail from one site to another, the MTA will look up the remote site in DNS to determine which host will receive mail for the destination. This process also occurs when mail is sent from a remote host to the MTA. [[dragonFly-mail-agent]] == DragonFly Mail Agent (DMA) DragonFly Mail Agent (DMA) is the default MTA in FreeBSD starting with version 14.0. man:dma[8] is a small Mail Transport Agent (MTA), designed for home and office use. It accepts mails from locally installed Mail User Agents (MUA) and delivers the mails either locally or to a remote destination. Remote delivery includes several features like TLS/SSL support and SMTP authentication. man:dma[8] is not intended as a replacement for real, big MTAs like man:sendmail[8] or man:postfix[1]. Consequently, man:dma[8] does not listen on port 25 for incoming connections. [[configuring-dragonfly-mail-agent]] === Configuring DragonFly Mail Agent (DMA) DMA comes with a default configuration that will be suitable for many deployments. Custom settings are defined in [.filename]#/etc/dma/dma.conf#, and SMTP authentication is configured in [.filename]#/etc/dma/auth.conf#. [[configuring-gmail-dma]] ==== Using DMA to Route Outgoing Mail through Gmail (STARTTLS:SMTP example) This example [.filename]#/etc/dma/dma.conf# can be used to send mail using Google's SMTP servers. [.programlisting] .... SMARTHOST smtp.gmail.com PORT 587 AUTHPATH /etc/dma/auth.conf SECURETRANSFER STARTTLS MASQUERADE username@gmail.com .... Authentication can be set with one line in [.filename]#/etc/dma/auth.conf#: [.programlisting] .... username@gmail.com|smtp.gmail.com:password .... Execute the following command to test the configuration: [source,shell] .... % echo this is a test | mail -v -s testing-email username@gmail.com .... [[configuring-fastmail-dma]] ==== Using DMA to Route Outgoing Mail through Fastmail (SSL/TLS example) This example [.filename]#/etc/dma/dma.conf# can be used to send mail using Fastmail's SMTP servers. [.programlisting] .... SMARTHOST smtp.fastmail.com PORT 465 AUTHPATH /etc/dma/auth.conf SECURETRANSFER MAILNAME example.server.com .... Authentication can be set with one line in [.filename]#/etc/dma/auth.conf#: [.programlisting] .... username@fastmail.com|smtp.fastmail.com:password .... Execute the following command to test the configuration: [source,shell] .... % echo this is a test | mail -v -s testing-email username@fastmail.com .... [[configuring-custom-dma]] ==== Using DMA to Route Outgoing Mail through a Custom Mail Host This example [.filename]#/etc/dma/dma.conf# can be used to send mail using a custom mail host. [.programlisting] .... SMARTHOST mail.example.org PORT 587 AUTHPATH /etc/dma/auth.conf SECURETRANSFER STARTTLS .... Authentication can be set with one line in [.filename]#/etc/dma/auth.conf#: [.programlisting] .... username@example.org|mail.example.org:password .... Execute the following command to test the configuration: [source,shell] .... % echo this is a test | mail -v -s testing-email username@example.org .... [[sendmail]] == Sendmail Sendmail is a venerable and versatile Mail Transfer Agent (MTA) with a long history in UNIX(R) and UNIX-like systems. It was a part of the FreeBSD base system until FreeBSD 13, offering robust email transport capabilities, extensive customization options, and support for complex routing and filtering. [[configuring-sendmail]] === Configuration Files The configuration files for Sendmail are located in [.filename]#/etc/mail/#. [.filename]#/etc/mail/access#:: This access database file defines which hosts or IP addresses have access to the local mail server and what kind of access they have. Hosts listed as `OK`, which is the default option, are allowed to send mail to this host as long as the mail's final destination is the local machine. Hosts listed as `REJECT` are rejected for all mail connections. Hosts listed as `RELAY` are allowed to send mail for any destination using this mail server. Hosts listed as `ERROR` will have their mail returned with the specified mail error. If a host is listed as `SKIP`, Sendmail will abort the current search for this entry without accepting or rejecting the mail. Hosts listed as `QUARANTINE` will have their messages held and will receive the specified text as the reason for the hold. + Examples of using these options for both IPv4 and IPv6 addresses can be found in the FreeBSD sample configuration, [.filename]#/etc/mail/access.sample#: + To configure the access database, use the format shown in the sample to make entries in [.filename]#/etc/mail/access#, but do not put a comment symbol (`+#+`) in front of the entries. Create an entry for each host or network whose access should be configured. Mail senders that match the left side of the table are affected by the action on the right side of the table. + Whenever this file is updated, update its database and restart Sendmail: + [source,shell] .... # makemap hash /etc/mail/access < /etc/mail/access # service sendmail restart .... [.filename]#/etc/mail/aliases#:: This database file contains a list of virtual mailboxes that are expanded to users, files, programs, or other aliases. Here are a few entries to illustrate the file format: + [.programlisting] .... root: localuser ftp-bugs: joe,eric,paul bit.bucket: /dev/null procmail: "|/usr/local/bin/procmail" .... + The mailbox name on the left side of the colon is expanded to the target(s) on the right. The first entry expands the `root` mailbox to the `localuser` mailbox, which is then looked up in the [.filename]#/etc/mail/aliases# database. If no match is found, the message is delivered to `localuser`. The second entry shows a mail list. Mail to `ftp-bugs` is expanded to the three local mailboxes `joe`, `eric`, and `paul`. A remote mailbox could be specified as _user@example.com_. The third entry shows how to write mail to a file, in this case [.filename]#/dev/null#. The last entry demonstrates how to send mail to a program, [.filename]#/usr/local/bin/procmail#, through a UNIX(R) pipe. Refer to man:aliases[5] for more information about the format of this file. + Whenever this file is updated, run `newaliases` to update and initialize the aliases database. [.filename]#/etc/mail/sendmail.cf#:: This is the master configuration file for Sendmail. It controls the overall behavior of Sendmail, including everything from rewriting email addresses to printing rejection messages to remote mail servers. Accordingly, this configuration file is quite complex. Fortunately, this file rarely needs to be changed for standard mail servers. + The master Sendmail configuration file can be built from man:m4[1] macros that define the features and behavior of Sendmail. Refer to [.filename]#/usr/src/contrib/sendmail/cf/README# for some of the details. + Whenever changes to this file are made, Sendmail needs to be restarted for the changes to take effect. [.filename]#/etc/mail/virtusertable#:: This database file maps mail addresses for virtual domains and users to real mailboxes. These mailboxes can be local, remote, aliases defined in [.filename]#/etc/mail/aliases#, or files. This allows multiple virtual domains to be hosted on one machine. + FreeBSD provides a sample configuration file in [.filename]#/etc/mail/virtusertable.sample# to further demonstrate its format. The following example demonstrates how to create custom entries using that format: + [.programlisting] .... root@example.com root postmaster@example.com postmaster@noc.example.net @example.com joe .... + This file is processed in a first match order. When an email address matches the address on the left, it is mapped to the local mailbox listed on the right. The format of the first entry in this example maps a specific email address to a local mailbox, whereas the format of the second entry maps a specific email address to a remote mailbox. Finally, any email address from `example.com` which has not matched any of the previous entries will match the last mapping and be sent to the local mailbox `joe`. When creating custom entries, use this format and add them to [.filename]#/etc/mail/virtusertable#. Whenever this file is edited, update its database and restart Sendmail: + [source,shell] .... # makemap hash /etc/mail/virtusertable < /etc/mail/virtusertable # service sendmail restart .... [.filename]#/etc/mail/relay-domains#:: In a default FreeBSD installation, Sendmail is configured to only send mail from the host it is running on. For example, if a POP server is available, users will be able to check mail from remote locations but they will not be able to send outgoing emails from outside locations. Typically, a few moments after the attempt, an email will be sent from `MAILER-DAEMON` with a `5.7 Relaying Denied` message. + The most straightforward solution is to add the ISP's FQDN to [.filename]#/etc/mail/relay-domains#. If multiple addresses are needed, add them one per line: + [.programlisting] .... your.isp.example.com other.isp.example.net users-isp.example.org www.example.org .... + After creating or editing this file, restart Sendmail with `service sendmail restart`. + Now any mail sent through the system by any host in this list, provided the user has an account on the system, will succeed. This allows users to send mail from the system remotely without opening the system up to relaying SPAM from the Internet. [[mail-changingmta]] == Changing the Mail Transfer Agent Starting with FreeBSD version 14.0, man:dma[8] is the default MTA, and before 14.0, the default MTA is man:sendmail[8]. However, the system administrator can change the system's MTA. A wide choice of alternative MTAs is available from the `mail` category of the FreeBSD Ports Collection. [WARNING] ==== If the default's outgoing mail service is disabled, it is important that it is replaced with an alternative mail delivery system. Otherwise, system functions such as man:periodic[8] will be unable to deliver their results by email. Many parts of the system expect a functional MTA. If applications continue to use the default binaries to try to send email after they are disabled, mail could go into an inactive queue and never be delivered. ==== [[replace-sendmail-dma]] === Replacing Sendmail with Other MTA In order to completely disable man:sendmail[8] execute the following commands: [source,shell] .... # sysrc sendmail_enable="NO" # sysrc sendmail_submit_enable="NO" # sysrc sendmail_outbound_enable="NO" # sysrc sendmail_msp_queue_enable="NO" .... To only disable man:sendmail[8]'s incoming mail service execute the following command: [source,shell] .... # sysrc sendmail_enable="NO" .... Then stop the man:sendmail[8] service: [source,shell] .... # service sendmail onestop .... Some extra configuration is needed as man:sendmail[8] is so ubiquitous that some software assumes it is already installed and configured. Check [.filename]#/etc/periodic.conf# and make sure that these values are set to `NO`. If this file does not exist, create it with these entries: [.programlisting] .... daily_clean_hoststat_enable="NO" daily_status_mail_rejects_enable="NO" daily_status_include_submit_mailq="NO" daily_submit_queuerun="NO" .... The next step is to install another MTA, man:dma[8] will be used in this example. As pointed above, man:dma[8] is the default MTA in FreeBSD starting with version 14.0. Therefore, it is only necessary to install it from the ports if you are using a previous version. To install it execute the following command: [source,shell] .... # pkg install dma .... Perform the configuration as indicated in <>. Then change all the entries in the file [.filename]#/etc/mail/mailer.conf# to man:dma[8]: [.programlisting] .... -# $FreeBSD$ -# # Execute the "real" sendmail program, named /usr/libexec/sendmail/sendmail # # If dma(8) is installed, an example mailer.conf that uses dma(8) instead can # be found in /usr/share/examples/dma # sendmail /usr/local/libexec/dma mailq /usr/local/libexec/dma newaliases /usr/local/libexec/dma .... [NOTE] ==== When using the version of man:dma[8] included in the base system, the paths will change to [.filename]#/usr/libexec/dma#. ==== To ensure that anything in the queue is flushed at boot or before shutdown, execute the following command: [source,shell] .... # sysrc dma_flushq_enable="YES" .... Once everything is configured, it is recommended to reboot the system. Rebooting provides the opportunity to ensure that the system is correctly configured to start the new MTA automatically on boot. [[replace-dma]] === Replacing DragonFly Mail Agent (DMA) with Other MTA As noted above, starting with FreeBSD version 14.0, the default MTA is DMA. In this example, package:mail/postfix[] will be used as the alternative MTA. Before installing package:mail/postfix[] some extra configuration is needed. Check [.filename]#/etc/periodic.conf# and make sure that these values are set to `NO`. If this file does not exist, create it with these entries: [.programlisting] .... daily_clean_hoststat_enable="NO" daily_status_mail_rejects_enable="NO" daily_status_include_submit_mailq="NO" daily_submit_queuerun="NO" .... Then install package:mail/postfix[]: [source,shell] .... # pkg install postfix .... To start package:mail/postfix[] at system boot execute the following command: [source,shell] .... # sysrc postfix_enable="YES" .... [TIP] ==== It is good practice to read the installation message after installing an application. Provides useful information about settings, etc. ==== If postfix is *not* already activated in [.filename]#/usr/local/etc/mail/mailer.conf# execute the following commands: [source,shell] .... mv /usr/local/etc/mail/mailer.conf /usr/local/etc/mail/mailer.conf.old install -d /usr/local/etc/mail install -m 0644 /usr/local/share/postfix/mailer.conf.postfix /usr/local/etc/mail/mailer.conf .... When employing SASL, ensure that postfix has access to read the sasldb file. This is accomplished by adding postfix to group mail and making the [.filename]#/usr/local/etc/sasldb*# file(s) readable by group mail (this should be the default for new installs). Once everything is configured, it is recommended to reboot the system. Rebooting provides the opportunity to ensure that the system is correctly configured to start the new MTA automatically on boot. [[mail-agents]] == Mail User Agents A MUA is an application that is used to send and receive email. As email "evolves" and becomes more complex, MUAs are becoming increasingly powerful and provide users increased functionality and flexibility. The `mail` category of the FreeBSD Ports Collection contains numerous MUAs. These include graphical email clients such as Evolution or Balsa and console based clients such as mutt or alpine. [[mail-command]] === mail man:mail[1] is the default MUA installed with FreeBSD. It is a console based MUA that offers the basic functionality required to send and receive text-based email. It provides limited attachment support and can only access local mailboxes. Although man:mail[1] does not natively support interaction with POP or IMAP servers, these mailboxes may be downloaded to a local `mbox` using an application such as fetchmail or getmail. In order to send and receive email, run man:mail[1]: [source,shell] .... % mail .... The contents of the user's mailbox in [.filename]#/var/mail# are automatically read by man:mail[1]. Should the mailbox be empty, the utility exits with a message indicating that no mail could be found. If mail exists, the application interface starts, and a list of messages will be displayed. Messages are automatically numbered, as can be seen in the following example: [.programlisting] .... Mail version 8.1 6/6/93. Type ? for help. "/var/mail/username": 3 messages 3 new >N 1 root@localhost Mon Mar 8 14:05 14/510 "test" N 2 root@localhost Mon Mar 8 14:05 14/509 "user account" N 3 root@localhost Mon Mar 8 14:05 14/509 "sample" .... Messages can now be read by typing kbd:[t] followed by the message number. This example reads the first email: [.programlisting] .... & t 1 Message 1: From root@localhost Mon Mar 8 14:05:52 2004 X-Original-To: username@localhost Delivered-To: username@localhost To: username@localhost Subject: test Date: Mon, 8 Mar 2004 14:05:52 +0200 (SAST) From: root@localhost (Charlie Root) This is a test message, please reply if you receive it. .... As seen in this example, the message will be displayed with full headers. To display the list of messages again, press kbd:[h]. If the email requires a reply, press either kbd:[R] or kbd:[r] man:mail[1] keys. kbd:[R] instructs man:mail[1] to reply only to the sender of the email, while kbd:[r] replies to all other recipients of the message. These commands can be suffixed with the mail number of the message to reply to. After typing the response, the end of the message should be marked by a single kbd:[.] on its own line. An example can be seen below: [.programlisting] .... & R 1 To: root@localhost Subject: Re: test Thank you, I did get your email. . EOT .... In order to send a new email, press kbd:[m], followed by the recipient email address. Multiple recipients may be specified by separating each address with the kbd:[,] delimiter. The subject of the message may then be entered, followed by the message contents. The end of the message should be specified by putting a single kbd:[.] on its own line. [.programlisting] .... & mail root@localhost Subject: I mastered mail Now I can send and receive email using mail ... :) . EOT .... While using man:mail[1], press kbd:[?] to display help at any time. Refer to man:mail[1] for more help on how to use man:mail[1]. [NOTE] ==== man:mail[1] was not designed to handle attachments and thus deals with them poorly. Newer MUAs handle attachments in a more intelligent way. ==== [[mutt-command]] === Mutt Mutt is a powerful MUA, with many features, including: * The ability to thread messages. * PGP support for digital signing and encryption of email. * MIME support. * Maildir support. * Highly customizable. Refer to link:http://www.mutt.org[http://www.mutt.org] for more information on Mutt. [TIP] ==== A Mutt fork called NeoMutt is worth mentioning, which brings added features. See more on the link:https://neomutt.org/about.html[NeoMutt website]. If NeoMutt was chosen, replace the following command examples from `mutt` to `neomutt`. ==== Mutt may be installed using the package:mail/mutt[] port. After the port has been installed, Mutt can be started by issuing the following command: [source,shell] .... % mutt .... Mutt will automatically read and display the contents of the user mailbox in [.filename]#/var/mail#. If no mails are found, Mutt will wait for commands from the user. The example below shows Mutt displaying a list of messages: image::mutt1.png[Mutt email client showing a list of messages] To read an email, select it using the cursor keys and press kbd:[Enter]. An example of Mutt displaying email can be seen below: image::mutt2.png[Mutt email client displaying an email] Similar to man:mail[1], Mutt can be used to reply only to the sender of the message as well as to all recipients. To reply only to the sender of the email, press kbd:[r]. To send a group reply to the original sender as well as all the message recipients, press kbd:[g]. [NOTE] ==== By default, Mutt uses the man:vi[1] editor for creating and replying to emails. Each user can customize this by creating or editing the [.filename]#.muttrc# in their home directory and setting the `editor` variable or by setting the `EDITOR` environment variable. Refer to link:http://www.mutt.org/[http://www.mutt.org/] for more information about configuring Mutt. ==== To compose a new mail message, press kbd:[m]. After a valid subject has been given, Mutt will start man:vi[1] so the email can be written. Once the contents of the email are complete, save and quit from `vi`. Mutt will resume, displaying a summary screen of the mail that is to be delivered. In order to send the mail, press kbd:[y]. An example of the summary screen can be seen below: image::mutt3.png[Mutt email client showing the summary screen] Mutt contains extensive help which can be accessed from most of the menus by pressing kbd:[?]. The top line also displays the keyboard shortcuts where appropriate. [[alpine-command]] === alpine alpine is aimed at a beginner user, but also includes some advanced features. [WARNING] ==== alpine has had several remote vulnerabilities discovered in the past, which allowed remote attackers to execute arbitrary code as users on the local system, by the action of sending a specially-prepared email. While _known_ problems have been fixed, alpine code is written in an insecure style and the FreeBSD Security Officer believes there are likely to be other undiscovered vulnerabilities. Users install alpine at their own risk. ==== The current version of alpine may be installed using the package:mail/alpine[] port. Once the port has installed, alpine can be started by issuing the following command: [source,shell] .... % alpine .... The first time alpine runs, it displays a greeting page with a brief introduction, as well as a request from the alpine development team to send an anonymous email message allowing them to judge how many users are using their client. To send this anonymous message, press kbd:[Enter]. Alternatively, press kbd:[E] to exit the greeting without sending an anonymous message. An example of the greeting page is shown below: image::pine1.png[alpine email client showing the greeting page] The main menu is then presented, which can be navigated using the cursor keys. This main menu provides shortcuts for the composing new mails, browsing mail directories, and administering address book entries. Below the main menu, relevant keyboard shortcuts to perform functions specific to the task at hand are shown. The default directory opened by alpine is [.filename]#inbox#. To view the message index, press kbd:[I], or select the [.guimenuitem]#MESSAGE INDEX# option shown below: image::pine2.png[alpine email client showing the default directory] The message index shows messages in the current directory and can be navigated by using the cursor keys. Highlighted messages can be read by pressing kbd:[Enter]. image::pine3.png[alpine email client showing the message index] In the screenshot below, a sample message is displayed by alpine. Contextual keyboard shortcuts are displayed at the bottom of the screen. An example of one of a shortcut is kbd:[r], which tells the MUA to reply to the current message being displayed. image::pine4.png[alpine email client showing an email] Replying to an email in alpine is done using the pico editor, which is installed by default with alpine. pico makes it easy to navigate the message and is easier for novice users to use than man:vi[1] or man:mail[1]. Once the reply is complete, the message can be sent by pressing kbd:[Ctrl+X]. alpine will ask for confirmation before sending the message. image::pine5.png[alpine email client showing the message compose window] alpine can be customized using the [.guimenuitem]#SETUP# option from the main menu. [[mail-advanced]] == Advanced Topics This section covers more involved topics such as mail configuration and setting up mail for an entire domain. [[mail-config]] === Basic Configuration Out of the box, one can send email to external hosts as long as [.filename]#/etc/resolv.conf# is configured or the network has access to a configured DNS server. To have email delivered to the MTA on the FreeBSD host, do one of the following: * Run a DNS server for the domain. * Get mail delivered directly to the FQDN for the machine. In order to have mail delivered directly to a host, it must have a permanent static IP address, not a dynamic IP address. If the system is behind a firewall, it must be configured to allow SMTP traffic. To receive mail directly at a host, one of these two must be configured: * Make sure that the lowest-numbered MX record in DNS points to the host's static IP address. * Make sure there is no MX entry in the DNS for the host. Either of the above will allow mail to be received directly at the host. Try this: [source,shell] .... # hostname .... The output should be similar to the following: [.programlisting] .... example.FreeBSD.org .... [source,shell] .... # host example.FreeBSD.org .... The output should be similar to the following: [.programlisting] .... example.FreeBSD.org has address 204.216.27.XX .... In this example, mail sent directly to mailto:yourlogin@example.FreeBSD.org[yourlogin@example.FreeBSD.org] should work without problems, assuming a full-featured MTA is running correctly on `example.FreeBSD.org`. Note that man:dma[8] does not listen on port 25 for incoming connections and cannot be used in this scenario. For this example: [source,shell] .... # host example.FreeBSD.org .... The output should be similar to the following: [.programlisting] .... example.FreeBSD.org has address 204.216.27.XX example.FreeBSD.org mail is handled (pri=10) by nevdull.FreeBSD.org .... All mail sent to `example.FreeBSD.org` will be collected on `nevdull` under the same username instead of being sent directly to your host. The above information is handled by the DNS server. The DNS record that carries mail routing information is the link:https://en.wikipedia.org/wiki/MX_record[mail exchanger record (MX record)]. If no MX record exists, mail will be delivered directly to the host by way of its IP address. The MX entry for `freefall.FreeBSD.org` at one time looked like this: [.programlisting] .... freefall MX 30 mail.crl.net freefall MX 40 agora.rdrop.com freefall MX 10 freefall.FreeBSD.org freefall MX 20 who.cdrom.com .... `freefall` had many MX entries. The lowest MX number is the host that receives mail directly, if available. If it is not accessible for some reason, the next lower-numbered host will accept messages temporarily, and pass it along when a lower-numbered host becomes available. Alternate MX sites should have separate Internet connections in order to be most useful. Your ISP can provide this service. [[mail-domain]] === Mail for a Domain When configuring an MTA for a network, any mail sent to hosts in its domain should be diverted to the MTA so that users can receive their mail on the master mail server. To make life easiest, a user account with the same _username_ should exist on both the MTA and the system with the MUA. Use man:adduser[8] to create the user accounts. [TIP] ==== In addition to adding local users to the host, there are alternative methods known as virtual users. Programs like link:https://www.cyrusimap.org/[Cyrus] and link:https://www.dovecot.org/[Dovecot] can be integrated into MTAs to handle users, mail storage, and also provide access via POP3 and IMAP. ==== The MTA must be the designated mail exchanger for each workstation on the network. This is done in the DNS configuration with an MX record: [.programlisting] .... example.FreeBSD.org A 204.216.27.XX ; Workstation MX 10 nevdull.FreeBSD.org ; Mailhost .... This will redirect mail for the workstation to the MTA no matter where the A record points. The mail is sent to the MX host. This must be configured on a DNS server. If the network does not run its own DNS server, talk to the ISP or DNS provider. The following is an example of virtual email hosting. Consider a customer with the domain `customer1.org`, where all the mail for `customer1.org` should be sent to `mail.myhost.com`. The DNS entry should look like this: [.programlisting] .... customer1.org MX 10 mail.myhost.com .... An `A` record is _not_ needed for `customer1.org` in order to only handle email for that domain. However, running `ping` against `customer1.org` will not work unless an `A` record exists for it. Tell the MTA which domains and/or hostnames it should accept mail for. Either of the following will work for Sendmail: * Add the hosts to [.filename]#/etc/mail/local-host-names# when using the `FEATURE(use_cw_file)`. * Add a `Cwyour.host.com` line to [.filename]#/etc/sendmail.cf#. [[outgoing-only]] === Setting Up to Send Only There are many instances where one may only want to send mail through a relay. Some examples are: * The computer is a desktop machine that needs to use programs such as man:mail[1], using the ISP's mail relay. * The computer is a server that does not handle mail locally, but needs to pass off all mail to a relay for processing. While any MTA is capable of filling this particular niche, it can be difficult to properly configure a full-featured MTA just to handle offloading mail. Programs such as Sendmail and Postfix are overkill for this use. Additionally, a typical Internet access service agreement may forbid one from running a "mail server". The easiest way to fulfill those needs is to use the man:dma[8] MTA included in the <>. For systems up to 13.2, need be to installed from ports. In addition to man:dma[8], third-party software can be used to achieve the same, like package:mail/ssmtp[]. [source,shell] .... # cd /usr/ports/mail/ssmtp # make install replace clean .... Once installed, package:mail/ssmtp[] can be configured with [.filename]#/usr/local/etc/ssmtp/ssmtp.conf#: [.programlisting] .... root=yourrealemail@example.com mailhub=mail.example.com rewriteDomain=example.com hostname=_HOSTNAME_ .... Use the real email address for `root`. Enter the ISP's outgoing mail relay in place of `mail.example.com`. Some ISPs call this the "outgoing mail server" or "SMTP server". Make sure to disable Sendmail, including the outgoing mail service. See <> for details. package:mail/ssmtp[] has some other options available. Refer to the examples in [.filename]#/usr/local/etc/ssmtp# or the manual page of ssmtp for more information. Setting up ssmtp in this manner allows any software on the computer that needs to send mail to function properly, while not violating the ISP's usage policy or allowing the computer to be hijacked for spamming. [[SMTP-Auth]] === SMTP Authentication in Sendmail Configuring SMTP authentication on the MTA provides a number of benefits. SMTP authentication adds a layer of security to Sendmail, and provides mobile users who switch hosts the ability to use the same MTA without the need to reconfigure their mail client's settings each time. Install package:security/cyrus-sasl2[] from the Ports Collection. This port supports a number of compile-time options. For the SMTP authentication method demonstrated in this example, make sure that `LOGIN` is not disabled. After installing package:security/cyrus-sasl2[], edit [.filename]#/usr/local/lib/sasl2/Sendmail.conf#, or create it if it does not exist, and add the following line: [.programlisting] .... pwcheck_method: saslauthd .... Next, install package:security/cyrus-sasl2-saslauthd[] and add execute the following command: [source,shell] .... # sysrc saslauthd_enable="YES" .... Finally, start the saslauthd daemon: [source,shell] .... # service saslauthd start .... This daemon serves as a broker for Sendmail to authenticate against the FreeBSD man:passwd[5] database. This saves the trouble of creating a new set of usernames and passwords for each user that needs to use SMTP authentication, and keeps the login and mail password the same. Next, edit [.filename]#/etc/make.conf# and add the following lines: [.programlisting] .... SENDMAIL_CFLAGS=-I/usr/local/include/sasl -DSASL SENDMAIL_LDADD=/usr/local/lib/libsasl2.so .... These lines provide Sendmail the proper configuration options for linking to package:cyrus-sasl2[] at compile time. Make sure that package:cyrus-sasl2[] has been installed before recompiling Sendmail. Recompile Sendmail by executing the following commands: [source,shell] .... # cd /usr/src/lib/libsmutil # make cleandir && make obj && make # cd /usr/src/lib/libsm # make cleandir && make obj && make # cd /usr/src/usr.sbin/sendmail # make cleandir && make obj && make && make install .... This compile should not have any problems if [.filename]#/usr/src# has not changed extensively and the shared libraries it needs are available. After Sendmail has been compiled and reinstalled, edit [.filename]#/etc/mail/freebsd.mc# or the local [.filename]#.mc#. Many administrators choose to use the output from man:hostname[1] as the name of [.filename]#.mc# for uniqueness. Add these lines: [.programlisting] .... dnl set SASL options TRUST_AUTH_MECH(`GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN')dnl define(`confAUTH_MECHANISMS', `GSSAPI DIGEST-MD5 CRAM-MD5 LOGIN')dnl .... These options configure the different methods available to Sendmail for authenticating users. To use a method other than pwcheck, refer to the Sendmail documentation. Finally, run man:make[1] while in [.filename]#/etc/mail#. That will run the new [.filename]#.mc# and create a [.filename]#.cf# named either [.filename]#freebsd.cf# or the name used for the local [.filename]#.mc#. Then, run `make install restart`, which will copy the file to [.filename]#sendmail.cf#, and properly restart Sendmail. For more information about this process, refer to [.filename]#/etc/mail/Makefile#. To test the configuration, use a MUA to send a test message. For further investigation, set the `LogLevel` of Sendmail to `13` and watch [.filename]#/var/log/maillog# for any errors. For more information, refer to http://www.sendmail.org/~ca/email/auth.html[SMTP authentication].