diff --git a/en_US.ISO8859-1/books/handbook/disks/chapter.sgml b/en_US.ISO8859-1/books/handbook/disks/chapter.sgml index de1318e8b6..31a7ca2fc1 100644 --- a/en_US.ISO8859-1/books/handbook/disks/chapter.sgml +++ b/en_US.ISO8859-1/books/handbook/disks/chapter.sgml @@ -1,2425 +1,2425 @@ Storage Synopsis This chapter covers the use of disks in FreeBSD. This includes memory-backed disks, network-attached disks, and standard SCSI/IDE storage devices. After reading this chapter, you will know: The terminology FreeBSD uses to describe the organization of data on a physical disk (partitions and slices). How to mount and unmount filesystems. How to add additional hard disks to your system. How to setup virtual filesystems, such as memory disks. How to use quotas to limit disk space usage. How to create and burn CDs and DVDs on FreeBSD. The various storage media options for backups. How to use backup programs available under FreeBSD. How to backup to floppy disks. Device Names The following is a list of physical storage devices supported in FreeBSD, and the device names associated with them. Physical Disk Naming Conventions Drive type Drive device name IDE hard drives ad IDE CDROM drives acd SCSI hard drives and USB Mass storage devices da SCSI CDROM drives cd Assorted non-standard CDROM drives mcd for Mitsumi CD-ROM, scd for Sony CD-ROM, matcd for Matsushita/Panasonic CD-ROM Floppy drives fd SCSI tape drives sa IDE tape drives ast Flash drives fla for DiskOnChip Flash device RAID drives myxd for Mylex, and amrd for AMI MegaRAID, idad for Compaq Smart RAID.
David O'Brien Originally contributed by Adding Disks disks adding Lets say we want to add a new SCSI 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 manufacturer. Due to the wide variations of procedures to do this, the details are beyond the scope of this document. Login as user root. After you have installed the drive, inspect /var/run/dmesg.boot to ensure the new disk was found. Continuing with our example, the newly added drive will be da1 and we want to mount it on /1 (if you are adding an IDE drive, the device name will be wd1 in pre-4.0 systems, or ad1 in most 4.X systems). partitions slices fdisk Because FreeBSD runs on IBM-PC compatible computers, it must take into account the PC BIOS partitions. These are different from the traditional BSD partitions. A PC disk has up to four BIOS partition entries. If the disk is going to be truly dedicated to FreeBSD, you can use the dedicated mode. Otherwise, FreeBSD will have to live within one of the PC BIOS partitions. FreeBSD calls the PC BIOS partitions slices so as not to confuse them with traditional BSD partitions. You may also use slices on a disk that is dedicated to FreeBSD, but used in a computer that also has another operating system installed. This is to not confuse the fdisk utility of the other operating system. In the slice case the drive will be added as /dev/da1s1e. This is read as: SCSI disk, unit number 1 (second SCSI disk), slice 1 (PC BIOS partition 1), and e BSD partition. In the dedicated case, the drive will be added simply as /dev/da1e. Using &man.sysinstall.8; sysinstall adding disks su Navigating <application>Sysinstall</application> You may use /stand/sysinstall to partition and label a new disk using its easy to use menus. Either login as user root or use the su command. Run /stand/sysinstall and enter the Configure menu. Within the FreeBSD Configuration Menu, scroll down and select the Fdisk option. <application>fdisk</application> Partition Editor Once inside fdisk, we can type A to use the entire disk for FreeBSD. When asked if you want to remain cooperative with any future possible operating systems, answer YES. Write the changes to the disk using W. Now exit the FDISK editor by typing q. Next you will be asked about the Master Boot Record. Since you are adding a disk to an already running system, choose None. Disk Label Editor BSD partitions Next, you need to exit sysinstall and start it again. Follow the directions above, although this time choose the Label option. This will enter the Disk Label Editor. This is where you will create the traditional BSD partitions. A disk can have up to eight partitions, labeled a-h. A few of the partition labels have special uses. The a partition is used for the root partition (/). Thus only your system disk (e.g, the disk you boot from) should have an a partition. The b partition is used for swap partitions, and you may have many disks with swap partitions. The c partition addresses the entire disk in dedicated mode, or the entire FreeBSD slice in slice mode. The other partitions are for general use. sysinstall's Label editor favors the e partition for non-root, non-swap partitions. Within the Label editor, create a single filesystem by typing C. When prompted if this will be a FS (filesystem) or swap, choose FS and type in a mount point (e.g, /mnt). When adding a disk in post-install mode, sysinstall will not create entries in /etc/fstab for you, so the mount point you specify is not important. You are now ready to write the new label to the disk and create a filesystem on it. Do this by typing W. Ignore any errors from sysinstall that it could not mount the new partition. Exit the Label Editor and sysinstall completely. Finish The last step is to edit /etc/fstab to add an entry for your new disk. Using Command Line Utilities Using Slices This setup will allow your disk to work correctly with other operating systems that might be installed on your computer and will not confuse other operating systems' fdisk utilities. It is recommended to use this method for new disk installs. Only use dedicated mode if you have a good reason to do so! &prompt.root; dd if=/dev/zero of=/dev/rda1 bs=1k count=1 &prompt.root; fdisk -BI da1 #Initialize your new disk &prompt.root; disklabel -B -w -r da1s1 auto #Label it. &prompt.root; disklabel -e da1s1 # Edit the disklabel just created and add any partitions. &prompt.root; mkdir -p /1 &prompt.root; newfs /dev/da1s1e # Repeat this for every partition you created. &prompt.root; mount -t ufs /dev/da1s1e /1 # Mount the partition(s) &prompt.root; vi /etc/fstab # Add the appropriate entry/entries to your /etc/fstab. If you have an IDE disk, substitute ad for da. On pre-4.X systems use wd. Dedicated OS/2 If you will not be sharing the new drive with another operating system, you may use the dedicated mode. Remember this mode can confuse Microsoft operating systems; however, no damage will be done by them. IBM's OS/2 however, will appropriate any partition it finds which it does not understand. &prompt.root; dd if=/dev/zero of=/dev/rda1 bs=1k count=1 &prompt.root; disklabel -Brw da1 auto &prompt.root; disklabel -e da1 # create the `e' partition &prompt.root; newfs -d0 /dev/rda1e &prompt.root; mkdir -p /1 &prompt.root; vi /etc/fstab # add an entry for /dev/da1e &prompt.root; mount /1 An alternate method is: &prompt.root; dd if=/dev/zero of=/dev/rda1 count=2 &prompt.root; disklabel /dev/rda1 | disklabel -BrR da1 /dev/stdin &prompt.root; newfs /dev/rda1e &prompt.root; mkdir -p /1 &prompt.root; vi /etc/fstab # add an entry for /dev/da1e &prompt.root; mount /1 + + + RAID - - Network, Memory, and File-Based Filesystems - virtual disks - - disks - virtual - + + Software RAID - Aside from the disks you physically insert into your computer: - floppies, CDs, hard drives, and so forth; other forms of disks - are understood by FreeBSD - the virtual - disks. + + + + + Christopher + Shumway + Written by + + + + + Valentino + Vaschetto + Marked up by + + + - NFS - Coda - - disks - memory - - These include network filesystems such as the Network Filesystem and Coda, memory-based - filesystems such as md and - file-backed filesystems created by vnconfig or - mdconfig. + ccd (Concatenated Disk Configuration) + When choosing a mass storage solution, the most important + factors to consider are speed, reliability, and cost. It is very + rare to have all three in favor, normally a fast, reliable mass + storage device is expensive, and to cut back on cost either speed + or reliability must be sacrificed. In designing my system, I + ranked the requirements by most favorable to least favorable. In + this situation, cost was the biggest factor. I needed a lot of + storage for a reasonable price. The next factor, speed, is not + quite as important, since most of the usage would be over a one + hundred megabit switched Ethernet, and that would most likely be + the bottleneck. The ability to spread the file input/output + operations out over several disks would be more than enough speed + for this network. Finally, the consideration of reliability was + an easy one to answer. All of the data being put on this mass + storage device was already backed up on CD-R's. This drive was + primarily here for online live storage for easy access, so if a + drive went bad, I could just replace it, rebuild the filesystem, + and copy back the data from CD-R's. - - vnconfig: File-Backed Filesystem - - disks - file-backed - + To sum it up, I need something that will give me the most + amount of storage space for my money. The cost of large IDE disks + are cheap these days. I found a place that was selling Western + Digital 30.7gb 5400 RPM IDE disks for about one-hundred and thirty + US dollars. I bought three of them, giving me approximately + ninety gigabytes of online storage. - &man.vnconfig.8; configures and enables vnode pseudo-disk - devices. A vnode is a representation - of a file, and is the focus of file activity. This means that - &man.vnconfig.8; uses files to create and operate a - filesystem. One possible use is the mounting of floppy or CD - images kept in files. + + Installing the Hardware - To mount an existing filesystem image: + I installed the hard drives in a system that already + had one IDE disk in as the system disk. The ideal solution + would be for each IDE disk to have its own IDE controller + and cable, but without fronting more costs to acquire a dual + IDE controller this would not be a possibility. So, I + jumpered two disks as slaves, and one as master. One went + on the first IDE controller as a slave to the system disk, + and the other two where slave/master on the secondary IDE + controller. - - Using vnconfig to mount an Existing Filesystem - Image + Upon reboot, the system BIOS was configured to + automatically detect the disks attached. More importantly, + FreeBSD detected them on reboot: - &prompt.root; vnconfig vn0 diskimage -&prompt.root; mount /dev/vn0c /mnt - + ad0: 19574MB <WDC WD205BA> [39770/16/63] at ata0-master UDMA33 +ad1: 29333MB <WDC WD307AA> [59598/16/63] at ata0-slave UDMA33 +ad2: 29333MB <WDC WD307AA> [59598/16/63] at ata1-master UDMA33 +ad3: 29333MB <WDC WD307AA> [59598/16/63] at ata1-slave UDMA33 - To create a new filesystem image with vnconfig: + At this point, if FreeBSD does not detect the disks, be + sure that you have jumpered them correctly. I have heard + numerous reports with problems using cable select instead of + true slave/master configuration. - - Creating a New File-Backed Disk with vnconfig - - &prompt.root; dd if=/dev/zero of=newimage bs=1k count=5k -5120+0 records in -5120+0 records out -&prompt.root; vnconfig -s labels -c vn0 newimage -&prompt.root; disklabel -r -w vn0 auto -&prompt.root; newfs vn0c -Warning: 2048 sector(s) in last cylinder unallocated -/dev/rvn0c: 10240 sectors in 3 cylinders of 1 tracks, 4096 sectors - 5.0MB in 1 cyl groups (16 c/g, 32.00MB/g, 1280 i/g) -super-block backups (for fsck -b #) at: - 32 -&prompt.root; mount /dev/vn0c /mnt -&prompt.root; df /mnt -Filesystem 1K-blocks Used Avail Capacity Mounted on -/dev/vn0c 4927 1 4532 0% /mnt - - + The next consideration was how to attach them as part of + the filesystem. I did a little research on &man.vinum.8; + () and + &man.ccd.4;. In this particular configuration, &man.ccd.4; + appeared to be a better choice mainly because it has fewer + parts. Less parts tends to indicate less chance of breakage. + Vinum appears to be a bit of an overkill for my needs. + - - md: Memory Filesystem - - disks - memory filesystem - + + Setting up the CCD - md is a simple, efficient means to create memory - filesystems. + CCD allows me to take + several identical disks and concatenate them into one + logical filesystem. In order to use + ccd, I need a kernel with + ccd support built into it. I + added this line to my kernel configuration file and rebuilt + the kernel: - Simply take a filesystem you have prepared with, for - example, &man.vnconfig.8;, and: + pseudo-device ccd 4 - - md Memory Disk + ccd support can also be + loaded as a kernel loadable module in FreeBSD 4.0 or + later. - &prompt.root; dd if=newimage of=/dev/md0 -5120+0 records in -5120+0 records out -&prompt.root; mount /dev/md0c /mnt -&prompt.root; df /mnt -Filesystem 1K-blocks Used Avail Capacity Mounted on -/dev/md0c 4927 1 4532 0% /mnt - - - - - - - - - Tom - Rhodes - Contributed by - - - - + To set up ccd, first I need + to disklabel the disks. Here is how I disklabeled + them: - Filesystem Snapshots + disklabel -r -w ad1 auto +disklabel -r -w ad2 auto +disklabel -r -w ad3 auto - - Filesystem Snapshots - Snapshots - - - FreeBSD 5.0 offers a new feature in conjunction with - Soft Updates: Filesystem snapshots. + This created a disklabel ad1c, ad2c and ad3c that + spans the entire disk. - Snapshots allow a user to create an image of specified file - systems and treat this image as a file. - Snapshot files must be created in the filesystem that the - action is performed on, and a user may create no more than 20 - snapshots per filesystem. 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 with the standard &man.rm.1; - command, like regular files. Snapshots may be removed in any order, - however all the used space may not be acquired as another snapshot will - possibly claim some of the blocks that were released. + The next step is to change the disklabel type. To do + that I had to edit the disklabel: - During initial creation, the flag (see &man.chflags.1; manual page) - is set on to ensure that not even root can write to the snapshot. - The &man.unlink.1; command makes an exception for snapshot files, - however, in which it allows them to be removed even - though they have the flag set, so it is not necessary to - clear the flag before removing a snapshot file. + disklabel -e ad1 +disklabel -e ad2 +disklabel -e ad3 - Snapshots are created with the &man.mount.8; command. To place - a snapshot of /var in the file - /var/snapshot/snap use the following - command: + This opened up the current disklabel on each disk + respectively in whatever editor the EDITOR + environment variable was set to, in my case, &man.vi.1;. + Inside the editor I had a section like this: -&prompt.root; mount -u -o snapshot /var/snapshot/snap /var + 8 partitions: +# size offset fstype [fsize bsize bps/cpg] + c: 60074784 0 unused 0 0 0 # (Cyl. 0 - 59597) - Once a snapshot has been created, there are several interesting - things that an administrator can do with them: - - - - Some administrators will use a snapshot file for backup purposes, - where the snapshot can be transfered to a CD or tape. - - - - File integrity, &man.fsck.8; may be ran on the snapshot file. - Assuming that the filesystem was clean when it was mounted, you - should always get a clean (and unchanging) result from running - &man.fsck.8; on the snapshot. This is essentially what the - background &man.fsck.8; process does. - - - - Run the &man.dump.8; utility on the snapshot. - A dump will be returned that is as consistent with the - filesystem as the timestamp of the snapshot. - - As of this writing &man.dump.8; has not yet - been changed to set the dumpdates file correctly, so - do not use this feature in production until that fix - is made. - - - - &man.mount.8; the snapshot as a frozen image of the filesystem. - To &man.mount.8; the snapshot - /var/snapshot/snap: + I needed to add a new "e" partition for &man.ccd.4; to + use. This usually can be copied of the "c" partition, but + the must be 4.2BSD. + Once I was done, + my disklabel should look like this: -&prompt.root; mdconfig -a -t vnode -f /var/snapshot/snap -u 4 -&prompt.root; mount -r /dev/md4 /mnt + 8 partitions: +# size offset fstype [fsize bsize bps/cpg] + c: 60074784 0 unused 0 0 0 # (Cyl. 0 - 59597) + e: 60074784 0 4.2BSD 0 0 0 # (Cyl. 0 - 59597) - - + - You can now walk the hierarchy of your frozen /var - filesystem mounted at /mnt. Everything will - be in the same state it was during the snapshot creation time. - The only exception being that any earlier snapshots will appear - as zero length files. When the use of a snapshot has delimited, - it can be unmounted with: + + Building the Filesystem -&prompt.root; umount /mnt -&prompt.root; mdconfig -d -u 4 + Now that I have all of the disks labeled, I needed to + build the ccd. To do that, I + used a utility called &man.ccdconfig.8;. + ccdconfig takes several arguments, the + first argument being the device to configure, in this case, + /dev/ccd0c. The device node for + ccd0c may not exist yet, so to + create it, perform the following commands: - For more information about and - filesystem snapshots, including technical papers, you can visit - Marshall Kirk McKusick's website at - http://www.mckusick.com - - - - Filesystem Quotas - - accounting - disk space - - disk quotas + cd /dev +sh MAKEDEV ccd0 - Quotas are an optional feature of the operating system that - allow you to limit the amount of disk space and/or the number of - files a user or members of a group may allocate on a per-file - system basis. This is used most often on timesharing systems where - it is desirable to limit the amount of resources any one user or - group of users may allocate. This will prevent one user or group - of users from consuming all of the available disk space. + The next argument ccdconfig expects + is the interleave for the filesystem. The interleave + defines the size of a stripe in disk blocks, normally five + hundred and twelve bytes. So, an interleave of thirty-two + would be sixteen thousand three hundred and eighty-four + bytes. - - Configuring Your System to Enable Disk Quotas + After the interleave comes the flags for + ccdconfig. If you want to enable drive + mirroring, you can specify a flag here. In this + configuration, I am not mirroring the + ccd, so I left it as zero. - Before attempting to use disk quotas, it is necessary to make - sure that quotas are configured in your kernel. This is done by - adding the following line to your kernel configuration - file: + The final arguments to ccdconfig + are the devices to place into the array. Putting it all + together I get this command: - options QUOTA + ccdconfig ccd0 32 0 /dev/ad1e /dev/ad2e /dev/ad3e - The stock GENERIC kernel does not have - this enabled by default, so you will have to configure, build and - install a custom kernel in order to use disk quotas. Please refer - to for more information on kernel - configuration. + This configures the ccd. + I can now &man.newfs.8; the filesystem. - Next you will need to enable disk quotas in - /etc/rc.conf. This is done by adding the - line: + newfs /dev/ccd0c - enable_quotas="YES" - - disk quotas - checking - - For finer control over your quota startup, there is an - additional configuration variable available. Normally on bootup, - the quota integrity of each filesystem is checked by the - quotacheck program. The - quotacheck facility insures that the data in - the quota database properly reflects the data on the filesystem. - This is a very time consuming process that will significantly - affect the time your system takes to boot. If you would like to - skip this step, a variable in /etc/rc.conf - is made available for the purpose: + - check_quotas="NO" + + Making it all Automatic - If you are running FreeBSD prior to 3.2-RELEASE, the - configuration is simpler, and consists of only one variable. Set - the following in your /etc/rc.conf: + Finally, if I want to be able to mount the + ccd, I need to + configure it first. I write out my current configuration to + /etc/ccd.conf using the following command: - check_quotas="YES" + ccdconfig -g > /etc/ccd.conf - Finally you will need to edit /etc/fstab - to enable disk quotas on a per-filesystem basis. This is where - you can either enable user or group quotas or both for all of your - filesystems. + When I reboot, the script /etc/rc + runs ccdconfig -C if /etc/ccd.conf + exists. This automatically configures the + ccd so it can be mounted. - To enable per-user quotas on a filesystem, add the - userquota option to the options field in the - /etc/fstab entry for the filesystem you want - to enable quotas on. For example: + If you are booting into single user mode, before you can + mount the ccd, you + need to issue the following command to configure the + array: - /dev/da1s2g /home ufs rw,userquota 1 2 + ccdconfig -C - Similarly, to enable group quotas, use the - groupquota option instead of - userquota. To enable both user and - group quotas, change the entry as follows: + Then, we need an entry for the + ccd in + /etc/fstab so it will be mounted at + boot time. - /dev/da1s2g /home ufs rw,userquota,groupquota 1 2 + /dev/ccd0c /media ufs rw 2 2 + + - By default, the quota files are stored in the root directory of - the filesystem with the names quota.user and - quota.group for user and group quotas - respectively. See &man.fstab.5; for more - information. Even though the &man.fstab.5; manual page says that - you can specify - an alternate location for the quota files, this is not recommended - because the various quota utilities do not seem to handle this - properly. + + The Vinum Volume Manager - At this point you should reboot your system with your new - kernel. /etc/rc will automatically run the - appropriate commands to create the initial quota files for all of - the quotas you enabled in /etc/fstab, so - there is no need to manually create any zero length quota - files. + The Vinum Volume Manager is a block device driver which + implements virtual disk drives. It isolates disk hardware + from the block device interface and maps data in ways which + result in an increase in flexibility, performance and + reliability compared to the traditional slice view of disk + storage. &man.vinum.8; implements the RAID-0, RAID-1 and + RAID-5 models, both individually and in combination. - In the normal course of operations you should not be required - to run the quotacheck, - quotaon, or quotaoff - commands manually. However, you may want to read their manual pages - just to be familiar with their operation. + See the for more + information about &man.vinum.8;. + - - Setting Quota Limits + + Hardware RAID + - disk quotas - limits + RAID + Hardware + FreeBSD also supports a variety of hardware RAID + controllers. In which case the actual RAID system + is built and controlled by the card itself. Using an on-card + BIOS, the card will control most of the disk operations + itself. The following is a brief setup using a Promise IDE RAID + controller. When this card is installed and the system started up, it will + display a prompt requesting information. Follow the on screen instructions + to enter the cards setup screen. From here a user should have the ability to + combine all the attached drives. When doing this, the disk(s) will look like + a single drive to FreeBSD. Other RAID levels can be setup + accordingly. + + + + + + + + + Mike + Meyer + Contributed by + + + + + - Once you have configured your system to enable quotas, verify - that they really are enabled. An easy way to do this is to - run: - - &prompt.root; quota -v - - You should see a one line summary of disk usage and current - quota limits for each filesystem that quotas are enabled - on. + Creating and Using Optical Media (CDs & DVDs) + + CDROMs + creating + - You are now ready to start assigning quota limits with the - edquota command. + + Introduction - You have several options on how to enforce limits on the - amount of disk space a user or group may allocate, and how many - files they may create. You may limit allocations based on disk - space (block quotas) or number of files (inode quotas) or a - combination of both. Each of these limits are further broken down - into two categories: hard and soft limits. + CDs have a number of features that differentiate them from + conventional disks. Initially, they were not writable by the + user. They are designed so that they can be read continuously without + delays to move the head between tracks. They are also much easier + to transport between systems than similarly sized media were at the + time. - hard limit - A hard limit may not be exceeded. Once a user reaches his - hard limit he may not make any further allocations on the file - system in question. For example, if the user has a hard limit of - 500 blocks on a filesystem and is currently using 490 blocks, the - user can only allocate an additional 10 blocks. Attempting to - allocate an additional 11 blocks will fail. - - soft limit - Soft limits, on the other hand, can be exceeded for a limited - amount of time. This period of time is known as the grace period, - which is one week by default. If a user stays over his or her - soft limit longer than the grace period, the soft limit will - turn into a hard limit and no further allocations will be allowed. - When the user drops back below the soft limit, the grace period - will be reset. - - The following is an example of what you might see when you run - the edquota command. When the - edquota command is invoked, you are placed into - the editor specified by the EDITOR environment - variable, or in the vi editor if the - EDITOR variable is not set, to allow you to edit - the quota limits. + CDs do have tracks, but this refers to a section of data to + be read continuously and not a physical property of the disk. To + produce a CD on FreeBSD, you prepare the data files that are going + to make up the tracks on the CD, then write the tracks to the + CD. - &prompt.root; edquota -u test + ISO 9660 + + filesystems + ISO-9660 + + The ISO 9660 filesystem was designed to deal with these + differences. It unfortunately codifies filesystem limits that were + common then. Fortunately, it provides an extension mechanism that + allows properly written CDs to exceed those limits while still + working with systems that do not support those extensions. - Quotas for user test: -/usr: blocks in use: 65, limits (soft = 50, hard = 75) - inodes in use: 7, limits (soft = 50, hard = 60) -/usr/var: blocks in use: 0, limits (soft = 50, hard = 75) - inodes in use: 0, limits (soft = 50, hard = 60) + + sysutils/mkisofs + + The sysutils/mkisofs + program is used to produce a data file containing an ISO 9660 file + system. It has options that support various extensions, and is + described below. You can install it with the + sysutils/mkisofs ports. - You will normally see two lines for each filesystem that has - quotas enabled. One line for the block limits, and one line for - inode limits. Simply change the value you want updated to modify - the quota limit. For example, to raise this user's block limit - from a soft limit of 50 and a hard limit of 75 to a soft limit of - 500 and a hard limit of 600, change: + + CD burner + ATAPI + + Which tool to use to burn the CD depends on whether your CD burner + is ATAPI or something else. ATAPI CD burners use the burncd program that is part of + the base system. SCSI and USB CD burners should use + cdrecord from + the sysutils/cdrtools port. - /usr: blocks in use: 65, limits (soft = 50, hard = 75) + burncd has a limited number of + supported drives. To find out if a drive is supported, see + CD-R/RW supported + drives. + - to: + + mkisofs - /usr: blocks in use: 65, limits (soft = 500, hard = 600) + sysutils/mkisofs produces an ISO 9660 filesystem + that is an image of a directory tree in the Unix filesystem name + space. The simplest usage is: - The new quota limits will be in place when you exit the - editor. + &prompt.root; mkisofs imagefile.iso /path/to/tree - Sometimes it is desirable to set quota limits on a range of - uids. This can be done by use of the option - on the edquota command. First, assign the - desired quota limit to a user, and then run - edquota -p protouser startuid-enduid. For - example, if user test has the desired quota - limits, the following command can be used to duplicate those quota - limits for uids 10,000 through 19,999: + + filesystems + ISO-9660 + + This command will create an imagefile + containing an ISO 9660 filesystem that is a copy of the tree at + /path/to/tree. In the process, it will + map the file names to names that fit the limitations of the + standard ISO 9660 filesystem, and will exclude files that have + names uncharacteristic of ISO filesystems. + + + filesystems + HFS + + + filesystems + Joliet + + A number of options are available to overcome those + restrictions. In particular, enables the + Rock Ridge extensions common to Unix systems, + enables Joliet extensions used by Microsoft systems, and + can be used to create HFS filesystems used + by MacOS. - &prompt.root; edquota -p test 10000-19999 - - For more information see &man.edquota.8;. - + For CDs that are going to be used only on FreeBSD systems, + can be used to disable all filename + restrictions. When used with , it produces a + filesystem image that is identical to the FreeBSD tree you started + from, though it may violate the ISO 9660 standard in a number of + ways. - - Checking Quota Limits and Disk Usage - disk quotas - checking + CDROMs + creating bootable + The last option of general use is . This is + used to specify the location of the 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. So, given that + /tmp/myboot holds a bootable FreeBSD system + with the boot image in + /tmp/myboot/boot/cdboot, you could produce the + image of an ISO 9660 filesystem in + /tmp/bootable.iso like so: - You can use either the quota or the - repquota commands to check quota limits and - disk usage. The quota command can be used to - check individual user or group quotas and disk usage. A user - may only examine his own quota, and the quota of a group he - is a member of. Only the super-user may view all user and group - quotas. The - repquota command can be used to get a summary - of all quotas and disk usage for filesystems with quotas - enabled. + &prompt.root; mkisofs -U -R -b boot/cdboot -o /tmp/bootable.iso /tmp/myboot - The following is some sample output from the - quota -v command for a user that has quota - limits on two filesystems. + Having done that, if you have vn + configured in your kernel, you can mount the filesystem with: - Disk quotas for user test (uid 1002): - Filesystem blocks quota limit grace files quota limit grace - /usr 65* 50 75 5days 7 50 60 - /usr/var 0 50 75 0 50 60 + &prompt.root; vnconfig -e vn0c /tmp/bootable.iso +&prompt.root; mount -t cd9660 /dev/vn0c /mnt - grace period - On the /usr filesystem in the above - example, this user is currently 15 blocks over the soft limit of - 50 blocks and has 5 days of the grace period left. Note the - asterisk * which indicates that the user is - currently over his quota limit. + At which point you can verify that /mnt + and /tmp/myboot are identical. - Normally filesystems that the user is not using any disk - space on will not show up in the output from the - quota command, even if he has a quota limit - assigned for that filesystem. The option - will display those filesystems, such as the - /usr/var filesystem in the above - example. + There are many other options you can use with + sysutils/mkisofs to fine-tune its behavior. In particular: + modifications to an ISO 9660 layout and the creation of Joilet + and HFS discs. See the &man.mkisofs.8; manual page for details. - - Quotas over NFS - NFS - - Quotas are enforced by the quota subsystem on the NFS server. - The &man.rpc.rquotad.8; daemon makes quota information available - to the &man.quota.1; command on NFS clients, allowing users on - those machines to see their quota statistics. - - Enable rpc.rquotad in - /etc/inetd.conf like so: - - rquotad/1 dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad + + burncd + + CDROMs + burning + + If you have an ATAPI CD burner, you can use the + burncd command to burn an ISO image onto a + CD. burncd is part of the base system, installed + as /usr/sbin/burncd. Usage is very simple, as + it has few options: - Now restart inetd: + &prompt.root; burncd cddevice data imagefile.iso fixate - &prompt.root; kill -HUP `cat /var/run/inetd.pid` + Will burn a copy of imagefile.iso on + cddevice. The default device is + /dev/acd0c. See &man.burncd.8; for options to + set the write speed, eject the CD after burning, and write audio + data. - - - - - - - Julio - Merino - Contributed by - - - - - Floppy disks + + cdrecord - Floppy disks are, nowadays, an old-fashioned medium to - store/share data. Although, there are still some times when you - need to use them, because you do not have any other removable - storage media or you need to use what you have saved in them on - any other computer. + If you do not have an ATAPI CD burner, you will have to use + cdrecord to burn your + CDs. cdrecord is not part of the base system; + you must install it from either the port at sysutils/cdrtools + or the appropriate + package. Changes to the base system can cause binary versions of + this program to fail, possibly resulting in a + coaster. You should therefore either upgrade the + port when you upgrade your system, or if you are tracking -STABLE, upgrade the port when a + new version becomes available. - This section will explain how to use floppy disks in - FreeBSD, that is, formating and copying/restoring data from - them. But... I really have written this to help you about how to - create forced-size floppies. + While cdrecord has many options, basic usage + is even simpler than burncd. Burning an ISO 9660 + image is done with: - - The device + &prompt.root; cdrecord device imagefile.iso + + The tricky part of using cdrecord is finding + the to use. To find the proper setting, use + the flag of cdrecord, + which might produce results like this: + + CDROMs + burning + + &prompt.root; cdrecord +Cdrecord 1.9 (i386-unknown-freebsd4.2) Copyright (C) 1995-2000 Jörg Schilling +Using libscg version 'schily-0.1' +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) * + + This lists the appropriate value for the + devices on the list. Locate your CD burner, and use the three + numbers separated by commas as the value for + . In this case, the CRW device is 1,5,0, so the + appropriate input would be + =1,5,0. There are easier + ways to specify this value; see &man.cdrecord.1; for + details. That is also the place to look for information on writing + audio tracks, controlling the speed, and other things. + + + + Duplicating Audio CDs + + You can duplicate an audio CD by extracting the audio data from + the CD to a series of files, and then writing these files to a blank + CD. The process is slightly different for ATAPI and SCSI + drives. + + + SCSI drives + + + Use cdda2wav to extract the audio. + + &prompt.user; cdda2wav -v255 -D2,0 -B -Owav + + + + Use cdrecord to write the + .wav files. + + &prompt.user; cdrecord -v dev=2,0 -dao -useinfo *.wav + + Make sure that 2.0 is set + appropriately, as described in . + + + + + ATAPI drives + + + The ATAPI CD driver makes each track available as + /dev/acddtn, + where d is the drive number, and + n is the track number. So the first + track on the first disk is + /dev/acd0t1. + + Make sure the appropriate files exist in + /dev. + + &prompt.root; cd /dev +&prompt.root; sh MAKEDEV acd0t99 + + + + Extract each track using &man.dd.1;. You must also use a + specific blocksize when extracting the files. + + &prompt.root; dd if=/dev/acd0t1 of=track1.cdr bs=2352 +&prompt.root; dd if=/dev/acd0t2 of=track2.cdr bs=2352 +... + + + + + Burn the extracted files to disk using + burncd. You must specify that these are audio + files, and that burncd should fixate the disk + when finished. + + &prompt.root; burncd -f /dev/acd0c audio track1.cdr track2.cdr ... fixate + + + + + + Duplicating Data CDs + + You can copy a data CD to a image file that is + functionally equivalent to the image file created with + sysutils/mkisofs, and you can use it to duplicate + any data CD. The example given here assumes that your CDROM + device is acd0. Substitute your + correct CDROM device. A c must be appended + to the end of the device name to indicate the entire partition + or, in the case of CDROMs, the entire disc. + + &prompt.root; dd if=/dev/acd0c of=file.iso bs=2048 + + Now that you have an image, you can burn it to CD as + described above. + + + + Using Data CDs + + Now that you have created a standard data CDROM, you + probably want to mount it and read the data on it. By + default, &man.mount.8; assumes that a filesystem is of type + ufs. If you try something like: + + &prompt.root; mount /dev/cd0c /mnt + + you will get a complaint about Incorrect super + block, and no mount. The CDROM is not a + UFS filesystem, so attempts to mount it + as such will fail. You just need to tell &man.mount.8; that + the filesystem is of type ISO9660, and + everything will work. You do this by specifying the + option &man.mount.8;. For + example, if you want to mount the CDROM device, + /dev/cd0c, under + /mnt, you would execute: + + &prompt.root; mount -t cd9660 /dev/cd0c /mnt + + Note that your device name + (/dev/cd0c in this example) could be + different, depending on the interface your CDROM uses. Also, + the option just executes + &man.mount.cd9660.8;. The above example could be shortened + to: + +&prompt.root; mount_cd9660 /dev/cd0c /mnt + + You can generally use data CDROMs from any vendor in this + way. Disks with certain ISO 9660 extensions might behave + oddly, however. For example, Joliet disks store all filenames + in two-byte Unicode characters. The FreeBSD kernel does not + speak Unicode (yet!), so non-English characters show up as + question marks. (If you are running FreeBSD 4.3 or later, the + CD9660 driver includes hooks to load an appropriate Unicode + conversion table on the fly. Modules for some of the common + encodings are available via the + sysutils/cd9660_unicode port.) + + Occasionally, you might get Device not + configured when trying to mount a CDROM. This + usually means that the CDROM drive thinks that there is no + disk in the tray, or that the drive is not visible on the bus. + It can take a couple of seconds for a CDROM drive to realize + that it has been fed, so be patient. + + Sometimes, a SCSI CDROM may be missed because it didn't + have enough time to answer the bus reset. If you have a SCSI + CDROM please add the following option to your kernel + configuration and rebuild your kernel. + + options SCSI_DELAY=15000 + + This tells your SCSI bus to pause 15 seconds during boot, + to give your CDROM drive every possible chance to answer the + bus reset. + + + + Burning Raw Data CDs + + You can choose to burn a file directly to CD, without + creating an ISO 9660 filesystem. Some people do this for + backup purposes. This runs more quickly than burning a + standard CD: + + &prompt.root; burncd -f /dev/acd1c -s 12 data archive.tar.gz fixate + + In order to retrieve the data burned to such a CD, you + must read data from the raw device node: + + &prompt.root; tar xzvf /dev/acd1c + + You cannot mount this disk as you would a normal CDROM. + Such a CDROM cannot be read under any operating system + except FreeBSD. If you want to be able to mount the CD, or + share data with another operating system, you must use + sysutils/mkisofs as described above. + + + + + + + + Julio + Merino + Contributed by + + + + + + Creating and Using Floppy Disks + + Floppy disks are, nowadays, an old-fashioned medium to + store/share data. Although, there are still some times when you + need to use them, because you do not have any other removable + storage media or you need to use what you have saved in them on + any other computer. + + This section will explain how to use floppy disks in + FreeBSD, that is, formating and copying/restoring data from + them. But... I really have written this to help you about how to + create forced-size floppies. + + + The device Floppy disks are accessed through entries in /dev (like any other device). To access the raw floppy disk you can use /dev/rfdX, where X stands for the drive number, usually 0. When the disk is formatted you can use /dev/fdX, or whichever of the other devices named /dev/fdXY, where Y stands for a letter. These are all the same. Other important devices are /dev/fdX.size, where size is a floppy disk size in kilobytes. These entries are used at low-level format time to determine the disk size. Sometimes you will have to (re)create these entries under /dev. To do it, you can issue: &prompt.root; cd /dev && ./MAKEDEV "fd*" Formatting A floppy disk needs to be low-level formated before it can be used. This is usually done by the vendor but you may want to do it to check media integrity or to force the disk capacity to be bigger. To format the floppy at a low-level fashion you need to use fdformat. This utility expects the device name as an argument. We will use those /dev/fdX.size devices, which will allow us to format the floppy to its real size, or force them. So you insert a new 3.5inch floppy disk in your drive and issue: &prompt.root; /usr/sbin/fdformat /dev/rfd0.1440 This will take a while... You should notice any disk error here (this can help you determining which disks are good or bad). To force the floppy disk size, we will use other entries in /dev. Get the same floppy and issue: &prompt.root; /usr/sbin/fdformat /dev/rfd0.1720 It will take some more time than before (forced disks are slower). When it finishes, you will have a 1720kb floppy disk, but for the moment you will not notice any difference. You may use other disk sizes that you can find in /dev, but the most stable/compatible is the 1720kb for 3.5inch disks. The disklabel After low-level formatting the disk, you will need to place a disklabel on it. This disklabel will be destroyed later, but it is needed by the system to determine the size of the disk and its geometry later. The new disklabel will take over the whole disk, and will contain all the proper information about the geometry of the normal or forced floppy. Take a look to /etc/disktab now; you will see geometry values of all kinds of floppy disks. You can run now disklabel like: &prompt.root; /sbin/disklabel -B -r -w /dev/rfd0 fdsize Replace fdsize with fd1440, fd1720 or whichever size you want. The last field instructs disklabel which entry to take from /etc/disktab to use. The filesystem Now your floppy is ready to be high-level formated. This will place a new filesystem on it, which will let FreeBSD read and write to the disk. After creating the new filesystem, the disklabel is destroyed, so if you want to reformat the disk, you will have to recreate the disklabel another time. You can choose now which filesystem to use on your floppy. You can use UFS or FAT, though UFS is not a good idea for floppies. Choose FAT which is nice for floppies. To put a new filesystem on the floppy do this: &prompt.root; /sbin/newfs_msdos /dev/fd0 As we created a disklabel before, newfs will be able to fetch disk data and construct the new filesystem. And now, your disk is ready for use... Using the floppy You have two choices to use the floppy. You can either mount the disk with mount_msdos, or you can use mtools. Mtools are great, but you will need to install them from the ports system. Try it; issue a mdir. If you forced the disk, you will notice its extra size! A last note about forced disks: they are compatible with practically all other operating systems without any external utility to read/write them. Microsoft systems will recognize them without problems. But note that there may be times when the floppy drive itself is not able to read them (this may happen with very old drives). + + + Creating and Using Data Tapes - - Backups to Floppies - - - Can I Use floppies for Backing Up My Data? - backup floppies - floppy disks + tape media + The major tape media are the 4mm, 8mm, QIC, mini-cartridge and + DLT. - Floppy disks are not really a suitable media for - making backups as: + + 4mm (DDS: Digital Data Storage) - - - The media is unreliable, especially over long periods of - time. + + tape media + DDS (4mm) tapes + + + tape media + QIC tapes + + 4mm tapes are replacing QIC as the workstation backup media of + choice. This trend accelerated greatly when Conner purchased Archive, + a leading manufacturer of QIC drives, and then stopped production of + QIC drives. 4mm drives are small and quiet but do not have the + reputation for reliability that is enjoyed by 8mm drives. The + cartridges are less expensive and smaller (3 x 2 x 0.5 inches, 76 x 51 + x 12 mm) than 8mm cartridges. 4mm, like 8mm, has comparatively short + head life for the same reason, both use helical scan. + + Data throughput on these drives starts ~150kB/s, peaking at ~500kB/s. + Data capacity starts at 1.3 GB and ends at 2.0 GB. Hardware + compression, available with most of these drives, approximately + doubles the capacity. Multi-drive tape library units can have 6 + drives in a single cabinet with automatic tape changing. Library + capacities reach 240 GB. + + The DDS-3 standard now supports tape capacities up to 12 GB (or + 24 GB compressed). + + 4mm drives, like 8mm drives, use helical-scan. All the benefits + and drawbacks of helical-scan apply to both 4mm and 8mm drives. + + Tapes should be retired from use after 2,000 passes or 100 full + backups. + + + + 8mm (Exabyte) + + tape media + Exabyte (8mm) tapes + + + 8mm tapes are the most common SCSI tape drives; they are the best + choice of exchanging tapes. Nearly every site has an Exabyte 2 GB 8mm + tape drive. 8mm drives are reliable, convenient and quiet. Cartridges + are inexpensive and small (4.8 x 3.3 x 0.6 inches; 122 x 84 x 15 mm). + One downside of 8mm tape is relatively short head and tape life due to + the high rate of relative motion of the tape across the heads. + + Data throughput ranges from ~250kB/s to ~500kB/s. Data sizes start + at 300 MB and go up to 7 GB. Hardware compression, available with + most of these drives, approximately doubles the capacity. These + drives are available as single units or multi-drive tape libraries + with 6 drives and 120 tapes in a single cabinet. Tapes are changed + automatically by the unit. Library capacities reach 840+ GB. + + The Exabyte Mammoth model supports 12 GB on one tape + (24 GB with compression) and costs approximately twice as much as + conventional tape drives. + + Data is recorded onto the tape using helical-scan, the heads are + positioned at an angle to the media (approximately 6 degrees). The + tape wraps around 270 degrees of the spool that holds the heads. The + spool spins while the tape slides over the spool. The result is a + high density of data and closely packed tracks that angle across the + tape from one edge to the other. + + + + QIC + + tape media + QIC-150 + + + QIC-150 tapes and drives are, perhaps, the most common tape drive + and media around. QIC tape drives are the least expensive "serious" + backup drives. The downside is the cost of media. QIC tapes are + expensive compared to 8mm or 4mm tapes, up to 5 times the price per GB + data storage. But, if your needs can be satisfied with a half-dozen + tapes, QIC may be the correct choice. QIC is the + most common tape drive. Every site has a QIC + drive of some density or another. Therein lies the rub, QIC has a + large number of densities on physically similar (sometimes identical) + tapes. QIC drives are not quiet. These drives audibly seek before + they begin to record data and are clearly audible whenever reading, + writing or seeking. QIC tapes measure (6 x 4 x 0.7 inches; 15.2 x + 10.2 x 1.7 mm). Mini-cartridges, which + also use 1/4" wide tape are discussed separately. Tape libraries and + changers are not available. + + Data throughput ranges from ~150kB/s to ~500kB/s. Data capacity + ranges from 40 MB to 15 GB. Hardware compression is available on many + of the newer QIC drives. QIC drives are less frequently installed; + they are being supplanted by DAT drives. + + Data is recorded onto the tape in tracks. The tracks run along + the long axis of the tape media from one end to the other. The number + of tracks, and therefore the width of a track, varies with the tape's + capacity. Most if not all newer drives provide backward-compatibility + at least for reading (but often also for writing). QIC has a good + reputation regarding the safety of the data (the mechanics are simpler + and more robust than for helical scan drives). + + Tapes should be retired from use after 5,000 backups. + + + + XXX* Mini-Cartridge + + + + + + DLT + + tape media + DLT + + + DLT has the fastest data transfer rate of all the drive types + listed here. The 1/2" (12.5mm) tape is contained in a single spool + cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm). The cartridge has a + swinging gate along one entire side of the cartridge. The drive + mechanism opens this gate to extract the tape leader. The tape leader + has an oval hole in it which the drive uses to "hook" the tape. The + take-up spool is located inside the tape drive. All the other tape + cartridges listed here (9 track tapes are the only exception) have + both the supply and take-up spools located inside the tape cartridge + itself. + + Data throughput is approximately 1.5MB/s, three times the throughput of + 4mm, 8mm, or QIC tape drives. Data capacities range from 10 GB to 20 GB + for a single drive. Drives are available in both multi-tape changers + and multi-tape, multi-drive tape libraries containing from 5 to 900 + tapes over 1 to 20 drives, providing from 50 GB to 9 TB of + storage. + + With compression, DLT Type IV format supports up to 70 GB + capacity. + + Data is recorded onto the tape in tracks parallel to the direction + of travel (just like QIC tapes). Two tracks are written at once. + Read/write head lifetimes are relatively long; once the tape stops + moving, there is no relative motion between the heads and the + tape. + + + + AIT + + tape media + AIT + + + AIT is a new format from Sony, and can hold up to 50 GB (with + compression) per tape. The tapes contain memory chips which retain an + index of the tape's contents. This index can be rapidly read by the + tape drive to determine the position of files on the tape, instead of + the several minutes that would be required for other tapes. Software + such as SAMS:Alexandria can operate forty or more AIT tape libraries, + communicating directly with the tape's memory chip to display the + contents on screen, determine what files were backed up to which + tape, locate the correct tape, load it, and restore the data from the + tape. + + Libraries like this cost in the region of $20,000, pricing them a + little out of the hobbyist market. + + + + Using a New Tape for the First Time + + The first time that you try to read or write a new, completely + blank tape, the operation will fail. The console messages should be + similar to: + + sa0(ncr1:4:0): NOT READY asc:4,1 +sa0(ncr1:4:0): Logical unit is in process of becoming ready + + The tape does not contain an Identifier Block (block number 0). + All QIC tape drives since the adoption of QIC-525 standard write an + Identifier Block to the tape. There are two solutions: + + mt fsf 1 causes the tape drive to write an + Identifier Block to the tape. + + Use the front panel button to eject the tape. + + Re-insert the tape and dump data to the tape. + + dump will report DUMP: End of tape + detected and the console will show: HARDWARE + FAILURE info:280 asc:80,96. + + rewind the tape using: mt rewind. + + Subsequent tape operations are successful. + + + + + Backups to Floppies + + + Can I Use floppies for Backing Up My Data? + backup floppies + floppy disks + + Floppy disks are not really a suitable media for + making backups as: + + + + The media is unreliable, especially over long periods of + time. Backing up and restoring is very slow. They have a very limited capacity (the days of backing up an entire hard disk onto a dozen or so floppies has long since passed). However, if you have no other method of backing up your data then floppy disks are better than no backup at all. If you do have to use floppy disks then ensure that you use good quality ones. Floppies that have been lying around the office for a couple of years are a bad choice. Ideally use new ones from a reputable manufacturer. So How Do I Backup My Data to Floppies? The best way to backup to floppy disk is to use tar with the (multi volume) option, which allows backups to span multiple floppies. To backup all the files in the current directory and sub-directory use this (as root): &prompt.root; tar Mcvf /dev/fd0 * When the first floppy is full tar will prompt you to insert the next volume (because tar is media independent it refers to volumes; in this context it means floppy disk). Prepare volume #2 for /dev/fd0 and hit return: This is repeated (with the volume number incrementing) until all the specified files have been archived. Can I Compress My Backups? tar - + gzip - - compression + + compression Unfortunately, tar will not allow the option to be used for multi-volume archives. You could, of course, gzip all the files, tar them to the floppies, then gunzip the files again! - How Do I Restore My Backups? - - To restore the entire archive use: - - &prompt.root; tar Mxvf /dev/fd0 - - There are two ways that you can use to restore only - specific files. First, you can start with the first floppy - and use: - - &prompt.root; tar Mxvf /dev/fd0 filename - - tar will prompt you to insert subsequent floppies until it - finds the required file. - - Alternatively, if you know which floppy the file is on then you - can simply insert that floppy and use the same command as above. Note - that if the first file on the floppy is a continuation from the - previous one then tar will warn you that it cannot - restore it, even if you have not asked it to! - - - - - - - - Mike - Meyer - Contributed by - - - - - - - Creating and Using Optical Media (CDs & DVDs) - - CDROMs - creating - - - - Introduction - - CDs have a number of features that differentiate them from - conventional disks. Initially, they were not writable by the - user. They are designed so that they can be read continuously without - delays to move the head between tracks. They are also much easier - to transport between systems than similarly sized media were at the - time. - - CDs do have tracks, but this refers to a section of data to - be read continuously and not a physical property of the disk. To - produce a CD on FreeBSD, you prepare the data files that are going - to make up the tracks on the CD, then write the tracks to the - CD. - - ISO 9660 - - filesystems - ISO-9660 - - The ISO 9660 filesystem was designed to deal with these - differences. It unfortunately codifies filesystem limits that were - common then. Fortunately, it provides an extension mechanism that - allows properly written CDs to exceed those limits while still - working with systems that do not support those extensions. - - - sysutils/mkisofs - - The sysutils/mkisofs - program is used to produce a data file containing an ISO 9660 file - system. It has options that support various extensions, and is - described below. You can install it with the - sysutils/mkisofs ports. - - - CD burner - ATAPI - - Which tool to use to burn the CD depends on whether your CD burner - is ATAPI or something else. ATAPI CD burners use the burncd program that is part of - the base system. SCSI and USB CD burners should use - cdrecord from - the sysutils/cdrtools port. - - burncd has a limited number of - supported drives. To find out if a drive is supported, see - CD-R/RW supported - drives. - - - - mkisofs - - sysutils/mkisofs produces an ISO 9660 filesystem - that is an image of a directory tree in the Unix filesystem name - space. The simplest usage is: - - &prompt.root; mkisofs imagefile.iso /path/to/tree - - - filesystems - ISO-9660 - - This command will create an imagefile - containing an ISO 9660 filesystem that is a copy of the tree at - /path/to/tree. In the process, it will - map the file names to names that fit the limitations of the - standard ISO 9660 filesystem, and will exclude files that have - names uncharacteristic of ISO filesystems. - - - filesystems - HFS - - - filesystems - Joliet - - A number of options are available to overcome those - restrictions. In particular, enables the - Rock Ridge extensions common to Unix systems, - enables Joliet extensions used by Microsoft systems, and - can be used to create HFS filesystems used - by MacOS. - - For CDs that are going to be used only on FreeBSD systems, - can be used to disable all filename - restrictions. When used with , it produces a - filesystem image that is identical to the FreeBSD tree you started - from, though it may violate the ISO 9660 standard in a number of - ways. - - - CDROMs - creating bootable - - The last option of general use is . This is - used to specify the location of the 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. So, given that - /tmp/myboot holds a bootable FreeBSD system - with the boot image in - /tmp/myboot/boot/cdboot, you could produce the - image of an ISO 9660 filesystem in - /tmp/bootable.iso like so: - - &prompt.root; mkisofs -U -R -b boot/cdboot -o /tmp/bootable.iso /tmp/myboot - - Having done that, if you have vn - configured in your kernel, you can mount the filesystem with: - - &prompt.root; vnconfig -e vn0c /tmp/bootable.iso -&prompt.root; mount -t cd9660 /dev/vn0c /mnt - - At which point you can verify that /mnt - and /tmp/myboot are identical. - - There are many other options you can use with - sysutils/mkisofs to fine-tune its behavior. In particular: - modifications to an ISO 9660 layout and the creation of Joilet - and HFS discs. See the &man.mkisofs.8; manual page for details. - - - - burncd - - CDROMs - burning - - If you have an ATAPI CD burner, you can use the - burncd command to burn an ISO image onto a - CD. burncd is part of the base system, installed - as /usr/sbin/burncd. Usage is very simple, as - it has few options: - - &prompt.root; burncd cddevice data imagefile.iso fixate - - Will burn a copy of imagefile.iso on - cddevice. The default device is - /dev/acd0c. See &man.burncd.8; for options to - set the write speed, eject the CD after burning, and write audio - data. - - - - cdrecord - - If you do not have an ATAPI CD burner, you will have to use - cdrecord to burn your - CDs. cdrecord is not part of the base system; - you must install it from either the port at sysutils/cdrtools - or the appropriate - package. Changes to the base system can cause binary versions of - this program to fail, possibly resulting in a - coaster. You should therefore either upgrade the - port when you upgrade your system, or if you are tracking -STABLE, upgrade the port when a - new version becomes available. - - While cdrecord has many options, basic usage - is even simpler than burncd. Burning an ISO 9660 - image is done with: - - &prompt.root; cdrecord device imagefile.iso - - The tricky part of using cdrecord is finding - the to use. To find the proper setting, use - the flag of cdrecord, - which might produce results like this: - - CDROMs - burning - - &prompt.root; cdrecord -Cdrecord 1.9 (i386-unknown-freebsd4.2) Copyright (C) 1995-2000 Jörg Schilling -Using libscg version 'schily-0.1' -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) * - - This lists the appropriate value for the - devices on the list. Locate your CD burner, and use the three - numbers separated by commas as the value for - . In this case, the CRW device is 1,5,0, so the - appropriate input would be - =1,5,0. There are easier - ways to specify this value; see &man.cdrecord.1; for - details. That is also the place to look for information on writing - audio tracks, controlling the speed, and other things. - - - - Duplicating Audio CDs - - You can duplicate an audio CD by extracting the audio data from - the CD to a series of files, and then writing these files to a blank - CD. The process is slightly different for ATAPI and SCSI - drives. - - - SCSI drives - - - Use cdda2wav to extract the audio. - - &prompt.user; cdda2wav -v255 -D2,0 -B -Owav - - - - Use cdrecord to write the - .wav files. - - &prompt.user; cdrecord -v dev=2,0 -dao -useinfo *.wav - - Make sure that 2.0 is set - appropriately, as described in . - - - - - ATAPI drives - - - The ATAPI CD driver makes each track available as - /dev/acddtn, - where d is the drive number, and - n is the track number. So the first - track on the first disk is - /dev/acd0t1. - - Make sure the appropriate files exist in - /dev. - - &prompt.root; cd /dev -&prompt.root; sh MAKEDEV acd0t99 - - - - Extract each track using &man.dd.1;. You must also use a - specific blocksize when extracting the files. - - &prompt.root; dd if=/dev/acd0t1 of=track1.cdr bs=2352 -&prompt.root; dd if=/dev/acd0t2 of=track2.cdr bs=2352 -... - - - - - Burn the extracted files to disk using - burncd. You must specify that these are audio - files, and that burncd should fixate the disk - when finished. - - &prompt.root; burncd -f /dev/acd0c audio track1.cdr track2.cdr ... fixate - - - - - - Duplicating Data CDs - - You can copy a data CD to a image file that is - functionally equivalent to the image file created with - sysutils/mkisofs, and you can use it to duplicate - any data CD. The example given here assumes that your CDROM - device is acd0. Substitute your - correct CDROM device. A c must be appended - to the end of the device name to indicate the entire partition - or, in the case of CDROMs, the entire disc. - - &prompt.root; dd if=/dev/acd0c of=file.iso bs=2048 - - Now that you have an image, you can burn it to CD as - described above. - - - - Using Data CDs - - Now that you have created a standard data CDROM, you - probably want to mount it and read the data on it. By - default, &man.mount.8; assumes that a filesystem is of type - ufs. If you try something like: - - &prompt.root; mount /dev/cd0c /mnt - - you will get a complaint about Incorrect super - block, and no mount. The CDROM is not a - UFS filesystem, so attempts to mount it - as such will fail. You just need to tell &man.mount.8; that - the filesystem is of type ISO9660, and - everything will work. You do this by specifying the - option &man.mount.8;. For - example, if you want to mount the CDROM device, - /dev/cd0c, under - /mnt, you would execute: - - &prompt.root; mount -t cd9660 /dev/cd0c /mnt - - Note that your device name - (/dev/cd0c in this example) could be - different, depending on the interface your CDROM uses. Also, - the option just executes - &man.mount.cd9660.8;. The above example could be shortened - to: - -&prompt.root; mount_cd9660 /dev/cd0c /mnt - - You can generally use data CDROMs from any vendor in this - way. Disks with certain ISO 9660 extensions might behave - oddly, however. For example, Joliet disks store all filenames - in two-byte Unicode characters. The FreeBSD kernel does not - speak Unicode (yet!), so non-English characters show up as - question marks. (If you are running FreeBSD 4.3 or later, the - CD9660 driver includes hooks to load an appropriate Unicode - conversion table on the fly. Modules for some of the common - encodings are available via the - sysutils/cd9660_unicode port.) - - Occasionally, you might get Device not - configured when trying to mount a CDROM. This - usually means that the CDROM drive thinks that there is no - disk in the tray, or that the drive is not visible on the bus. - It can take a couple of seconds for a CDROM drive to realize - that it has been fed, so be patient. - - Sometimes, a SCSI CDROM may be missed because it didn't - have enough time to answer the bus reset. If you have a SCSI - CDROM please add the following option to your kernel - configuration and rebuild your kernel. - - options SCSI_DELAY=15000 - - This tells your SCSI bus to pause 15 seconds during boot, - to give your CDROM drive every possible chance to answer the - bus reset. - - - - Burning Raw Data CDs - - You can choose to burn a file directly to CD, without - creating an ISO 9660 filesystem. Some people do this for - backup purposes. This runs more quickly than burning a - standard CD: - - &prompt.root; burncd -f /dev/acd1c -s 12 data archive.tar.gz fixate - - In order to retrieve the data burned to such a CD, you - must read data from the raw device node: - - &prompt.root; tar xzvf /dev/acd1c - - You cannot mount this disk as you would a normal CDROM. - Such a CDROM cannot be read under any operating system - except FreeBSD. If you want to be able to mount the CD, or - share data with another operating system, you must use - sysutils/mkisofs as described above. - - - - - RAID - - - Software RAID - - - - - - Christopher - Shumway - Written by - - - - - Valentino - Vaschetto - Marked up by - - - - - ccd (Concatenated Disk Configuration) - When choosing a mass storage solution, the most important - factors to consider are speed, reliability, and cost. It is very - rare to have all three in favor, normally a fast, reliable mass - storage device is expensive, and to cut back on cost either speed - or reliability must be sacrificed. In designing my system, I - ranked the requirements by most favorable to least favorable. In - this situation, cost was the biggest factor. I needed a lot of - storage for a reasonable price. The next factor, speed, is not - quite as important, since most of the usage would be over a one - hundred megabit switched Ethernet, and that would most likely be - the bottleneck. The ability to spread the file input/output - operations out over several disks would be more than enough speed - for this network. Finally, the consideration of reliability was - an easy one to answer. All of the data being put on this mass - storage device was already backed up on CD-R's. This drive was - primarily here for online live storage for easy access, so if a - drive went bad, I could just replace it, rebuild the filesystem, - and copy back the data from CD-R's. - - To sum it up, I need something that will give me the most - amount of storage space for my money. The cost of large IDE disks - are cheap these days. I found a place that was selling Western - Digital 30.7gb 5400 RPM IDE disks for about one-hundred and thirty - US dollars. I bought three of them, giving me approximately - ninety gigabytes of online storage. - - - Installing the Hardware - - I installed the hard drives in a system that already - had one IDE disk in as the system disk. The ideal solution - would be for each IDE disk to have its own IDE controller - and cable, but without fronting more costs to acquire a dual - IDE controller this would not be a possibility. So, I - jumpered two disks as slaves, and one as master. One went - on the first IDE controller as a slave to the system disk, - and the other two where slave/master on the secondary IDE - controller. - - Upon reboot, the system BIOS was configured to - automatically detect the disks attached. More importantly, - FreeBSD detected them on reboot: - - ad0: 19574MB <WDC WD205BA> [39770/16/63] at ata0-master UDMA33 -ad1: 29333MB <WDC WD307AA> [59598/16/63] at ata0-slave UDMA33 -ad2: 29333MB <WDC WD307AA> [59598/16/63] at ata1-master UDMA33 -ad3: 29333MB <WDC WD307AA> [59598/16/63] at ata1-slave UDMA33 - - At this point, if FreeBSD does not detect the disks, be - sure that you have jumpered them correctly. I have heard - numerous reports with problems using cable select instead of - true slave/master configuration. - - The next consideration was how to attach them as part of - the filesystem. I did a little research on &man.vinum.8; - () and - &man.ccd.4;. In this particular configuration, &man.ccd.4; - appeared to be a better choice mainly because it has fewer - parts. Less parts tends to indicate less chance of breakage. - Vinum appears to be a bit of an overkill for my needs. - - - - Setting up the CCD - - CCD allows me to take - several identical disks and concatenate them into one - logical filesystem. In order to use - ccd, I need a kernel with - ccd support built into it. I - added this line to my kernel configuration file and rebuilt - the kernel: - - pseudo-device ccd 4 - - ccd support can also be - loaded as a kernel loadable module in FreeBSD 4.0 or - later. - - To set up ccd, first I need - to disklabel the disks. Here is how I disklabeled - them: - - disklabel -r -w ad1 auto -disklabel -r -w ad2 auto -disklabel -r -w ad3 auto - - This created a disklabel ad1c, ad2c and ad3c that - spans the entire disk. - - The next step is to change the disklabel type. To do - that I had to edit the disklabel: - - disklabel -e ad1 -disklabel -e ad2 -disklabel -e ad3 - - This opened up the current disklabel on each disk - respectively in whatever editor the EDITOR - environment variable was set to, in my case, &man.vi.1;. - Inside the editor I had a section like this: - - 8 partitions: -# size offset fstype [fsize bsize bps/cpg] - c: 60074784 0 unused 0 0 0 # (Cyl. 0 - 59597) - - I needed to add a new "e" partition for &man.ccd.4; to - use. This usually can be copied of the "c" partition, but - the must be 4.2BSD. - Once I was done, - my disklabel should look like this: - - 8 partitions: -# size offset fstype [fsize bsize bps/cpg] - c: 60074784 0 unused 0 0 0 # (Cyl. 0 - 59597) - e: 60074784 0 4.2BSD 0 0 0 # (Cyl. 0 - 59597) - - - - - Building the Filesystem - - Now that I have all of the disks labeled, I needed to - build the ccd. To do that, I - used a utility called &man.ccdconfig.8;. - ccdconfig takes several arguments, the - first argument being the device to configure, in this case, - /dev/ccd0c. The device node for - ccd0c may not exist yet, so to - create it, perform the following commands: - - cd /dev -sh MAKEDEV ccd0 - - The next argument ccdconfig expects - is the interleave for the filesystem. The interleave - defines the size of a stripe in disk blocks, normally five - hundred and twelve bytes. So, an interleave of thirty-two - would be sixteen thousand three hundred and eighty-four - bytes. - - After the interleave comes the flags for - ccdconfig. If you want to enable drive - mirroring, you can specify a flag here. In this - configuration, I am not mirroring the - ccd, so I left it as zero. - - The final arguments to ccdconfig - are the devices to place into the array. Putting it all - together I get this command: - - ccdconfig ccd0 32 0 /dev/ad1e /dev/ad2e /dev/ad3e - - This configures the ccd. - I can now &man.newfs.8; the filesystem. - - newfs /dev/ccd0c - - - - - Making it all Automatic - - Finally, if I want to be able to mount the - ccd, I need to - configure it first. I write out my current configuration to - /etc/ccd.conf using the following command: - - ccdconfig -g > /etc/ccd.conf - - When I reboot, the script /etc/rc - runs ccdconfig -C if /etc/ccd.conf - exists. This automatically configures the - ccd so it can be mounted. - - If you are booting into single user mode, before you can - mount the ccd, you - need to issue the following command to configure the - array: - - ccdconfig -C - - Then, we need an entry for the - ccd in - /etc/fstab so it will be mounted at - boot time. - - /dev/ccd0c /media ufs rw 2 2 - - - - - The Vinum Volume Manager - - The Vinum Volume Manager is a block device driver which - implements virtual disk drives. It isolates disk hardware - from the block device interface and maps data in ways which - result in an increase in flexibility, performance and - reliability compared to the traditional slice view of disk - storage. &man.vinum.8; implements the RAID-0, RAID-1 and - RAID-5 models, both individually and in combination. - - See the for more - information about &man.vinum.8;. - - - - - Hardware RAID - - - RAID - Hardware - - FreeBSD also supports a variety of hardware RAID - controllers. In which case the actual RAID system - is built and controlled by the card itself. Using an on-card - BIOS, the card will control most of the disk operations - itself. The following is a brief setup using a Promise IDE RAID - controller. When this card is installed and the system started up, it will - display a prompt requesting information. Follow the on screen instructions - to enter the cards setup screen. From here a user should have the ability to - combine all the attached drives. When doing this, the disk(s) will look like - a single drive to FreeBSD. Other RAID levels can be setup - accordingly. - + How Do I Restore My Backups? + + To restore the entire archive use: + + &prompt.root; tar Mxvf /dev/fd0 + + There are two ways that you can use to restore only + specific files. First, you can start with the first floppy + and use: + + &prompt.root; tar Mxvf /dev/fd0 filename + + tar will prompt you to insert subsequent floppies until it + finds the required file. + + Alternatively, if you know which floppy the file is on then you + can simply insert that floppy and use the same command as above. Note + that if the first file on the floppy is a continuation from the + previous one then tar will warn you that it cannot + restore it, even if you have not asked it to! - + - Backup Programs + Backup Basics backup software and basics The three major backup programs are &man.dump.8;, &man.tar.1;, and &man.cpio.1;. - + Dump and Restore backup software dump / restore - - dump + + dump restore The traditional Unix backup programs are dump and restore. They operate on the drive as a collection of disk blocks, below the abstractions of files, links and directories that are created by the filesystems. dump backs up an entire filesystem on a device. It is unable to backup only part of a filesystem or a directory tree that spans more than one filesystem. dump does not write files and directories to tape, but rather writes the raw data blocks that comprise files and directories. If you use dump on your root directory, you would not back up /home, /usr or many other directories since these are typically mount points for other filesystems or symbolic links into those filesystems. dumphas quirks that remain from its early days in Version 6 of AT&T Unix (circa 1975). The default parameters are suitable for 9-track tapes (6250 bpi), not the high-density media available today (up to 62,182 ftpi). These defaults must be overridden on the command line to utilize the capacity of current tape drives. rhosts It is also possible to backup data across the network to a tape drive attached to another computer with rdump and rrestore. Both programs rely upon rcmd and ruserok to access the remote tape drive. Therefore, the user performing the backup must have rhosts access to the remote computer. The arguments to rdump and rrestore must be suitable to use on the remote computer. (e.g. When rdumping from a FreeBSD computer to an Exabyte tape drive connected to a Sun called komodo, use: /sbin/rdump 0dsbfu 54000 13000 126 komodo:/dev/nrsa8 /dev/rda0a 2>&1) Beware: there are security implications to allowing rhosts commands. Evaluate your situation carefully. It is also possible to use rdump and rrestore in a more secure fashion over ssh. Using <command>rdump</command> over <application>ssh</application> &prompt.root; /sbin/dump -0uan -f - /usr | gzip -2 | ssh1 -c blowfish \ targetuser@targetmachine.example.com dd of=/mybigfiles/dump-usr-l0.gz <command>tar</command> backup software tar - + &man.tar.1; also dates back to Version 6 of AT&T Unix (circa 1975). tar operates in cooperation with the filesystem; tar writes files and directories to tape. tar does not support the full range of options that are available from &man.cpio.1;, but tar does not require the unusual command pipeline that cpio uses. tar Most versions of tar do not support backups across the network. The GNU version of tar, which FreeBSD utilizes, supports remote devices using the same syntax as rdump. To tar to an Exabyte tape drive connected to a Sun called komodo, use: /usr/bin/tar cf komodo:/dev/nrsa8 . 2>&1. For versions without remote device support, you can use a pipeline and rsh to send the data to a remote tape drive. &prompt.root; tar cf - . | rsh hostname dd of=tape-device obs=20b If you are worried about the security of backing up over a network you should use the ssh command instead of rsh. - + <command>cpio</command> backup software cpio &man.cpio.1; is the original Unix file interchange tape program for magnetic media. cpio has options (among many others) to perform byte-swapping, write a number of different archive formats, and pipe the data to other programs. This last feature makes cpio and excellent choice for installation media. cpio does not know how to walk the directory tree and a list of files must be provided through stdin. cpio cpio does not support backups across the network. You can use a pipeline and rsh to send the data to a remote tape drive. &prompt.root; for f in directory_list; do find $f >> backup.list done &prompt.root; cpio -v -o --format=newc < backup.list | ssh user@host "cat > backup_device" Where directory_list is the list of directories you want to back up, user@host is the user/hostname combination that will be performing the backups, and backup_device is where the backups should be written to (e.g., /dev/nrsa0). - + <command>pax</command> backup software pax pax POSIX IEEE &man.pax.1; is IEEE/POSIX's answer to tar and cpio. Over the years the various versions of tar and cpio have gotten slightly incompatible. So rather than fight it out to fully standardize them, POSIX created a new archive utility. pax attempts to read and write many of the various cpio and tar formats, plus new formats of its own. Its command set more resembles cpio than tar. <application>Amanda</application> backup software Amanda - + Amanda - + Amanda (Advanced Maryland Network Disk Archiver) is a client/server backup system, rather than a single program. An Amanda server will backup to a single tape drive any number of computers that have Amanda clients and a network connection to the Amanda server. A common problem at sites with a number of large disks is that the length of time required to backup to data directly to tape exceeds the amount of time available for the task. Amanda solves this problem. Amanda can use a holding disk to backup several filesystems at the same time. Amanda creates archive sets: a group of tapes used over a period of time to create full backups of all the filesystems listed in Amanda's configuration file. The archive set also contains nightly incremental (or differential) backups of all the filesystems. Restoring a damaged filesystem requires the most recent full backup and the incremental backups. The configuration file provides fine control of backups and the network traffic that Amanda generates. Amanda will use any of the above backup programs to write the data to tape. Amanda is available as either a port or a package, it is not installed by default. Do Nothing - + Do nothing is not a computer program, but it is the most widely used backup strategy. There are no initial costs. There is no backup schedule to follow. Just say no. If something happens to your data, grin and bear it! If your time and your data is worth little to nothing, then Do nothing is the most suitable backup program for your computer. But beware, Unix is a useful tool, you may find that within six months you have a collection of files that are valuable to you. Do nothing is the correct backup method for /usr/obj and other directory trees that can be exactly recreated by your computer. An example is the files that comprise the HTML or PostScript version of this Handbook. These document formats have been created from SGML input files. Creating backups of the HTML or PostScript files is not necessary. The SGML files are backed up regularly. - + Which Backup Program Is Best? LISA &man.dump.8; Period. Elizabeth D. Zwicky torture tested all the backup programs discussed here. The clear choice for preserving all your data and all the peculiarities of Unix filesystems is dump. Elizabeth created filesystems containing a large variety of unusual conditions (and some not so unusual ones) and tested each program by doing a backup and restore of those filesystems. The peculiarities included: files with holes, files with holes and a block of nulls, files with funny characters in their names, unreadable and unwritable files, devices, files that change size during the backup, files that are created/deleted during the backup and more. She presented the results at LISA V in Oct. 1991. See torture-testing Backup and Archive Programs. - + Emergency Restore Procedure - + Before the Disaster There are only four steps that you need to perform in preparation for any disaster that may occur. disklabel - + First, print the disklabel from each of your disks (e.g. disklabel da0 | lpr), your filesystem table (/etc/fstab) and all boot messages, two copies of each. - fix-it floppies + fix-it floppies Second, determine that the boot and fix-it floppies (boot.flp and fixit.flp) have all your devices. The easiest way to check is to reboot your machine with the boot floppy in the floppy drive and check the boot messages. If all your devices are listed and functional, skip on to step three. Otherwise, you have to create two custom bootable floppies which have a kernel that can mount all of your disks and access your tape drive. These floppies must contain: fdisk, disklabel, newfs, mount, and whichever backup program you use. These programs must be statically linked. If you use dump, the floppy must contain restore. - Third, create backup tapes regularly. Any changes that you make - after your last backup may be irretrievably lost. Write-protect the - backup tapes. + Third, create backup tapes regularly. Any changes that you make + after your last backup may be irretrievably lost. Write-protect the + backup tapes. + + Fourth, test the floppies (either boot.flp + and fixit.flp or the two custom bootable + floppies you made in step two.) and backup tapes. Make notes of the + procedure. Store these notes with the bootable floppy, the + printouts and the backup tapes. You will be so distraught when + restoring that the notes may prevent you from destroying your backup + tapes (How? In place of tar xvf /dev/rsa0, you + might accidentally type tar cvf /dev/rsa0 and + over-write your backup tape). + + For an added measure of security, make bootable floppies and two + backup tapes each time. Store one of each at a remote location. A + remote location is NOT the basement of the same office building. A + number of firms in the World Trade Center learned this lesson the + hard way. A remote location should be physically separated from + your computers and disk drives by a significant distance. + + + A Script for Creating a Bootable Floppy + + /mnt/sbin/init +gzip -c -best /sbin/fsck > /mnt/sbin/fsck +gzip -c -best /sbin/mount > /mnt/sbin/mount +gzip -c -best /sbin/halt > /mnt/sbin/halt +gzip -c -best /sbin/restore > /mnt/sbin/restore + +gzip -c -best /bin/sh > /mnt/bin/sh +gzip -c -best /bin/sync > /mnt/bin/sync + +cp /root/.profile /mnt/root + +cp -f /dev/MAKEDEV /mnt/dev +chmod 755 /mnt/dev/MAKEDEV + +chmod 500 /mnt/sbin/init +chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt +chmod 555 /mnt/bin/sh /mnt/bin/sync +chmod 6555 /mnt/sbin/restore + +# +# create the devices nodes +# +cd /mnt/dev +./MAKEDEV std +./MAKEDEV da0 +./MAKEDEV da1 +./MAKEDEV da2 +./MAKEDEV sa0 +./MAKEDEV pty0 +cd / + +# +# create minimum filesystem table +# +cat > /mnt/etc/fstab < /mnt/etc/passwd < /mnt/etc/master.passwd < + + + + + + + After the Disaster + + The key question is: did your hardware survive? You have been + doing regular backups so there is no need to worry about the + software. + + If the hardware has been damaged. First, replace those parts + that have been damaged. + + If your hardware is okay, check your floppies. If you are using + a custom boot floppy, boot single-user (type -s + at the boot: prompt). Skip the following + paragraph. + + If you are using the boot.flp and + fixit.flp floppies, keep reading. Insert the + boot.flp floppy in the first floppy drive and + boot the computer. The original install menu will be displayed on + the screen. Select the Fixit--Repair mode with CDROM or + floppy. option. Insert the + fixit.flp when prompted. + restore and the other programs that you need are + located in /mnt2/stand. + + Recover each filesystem separately. + + + mount + + root partition + + disklabel + + + newfs + + Try to mount (e.g. mount /dev/da0a + /mnt) the root partition of your first disk. If the + disklabel was damaged, use disklabel to re-partition and + label the disk to match the label that you printed and saved. Use + newfs to re-create the filesystems. Re-mount the root + partition of the floppy read-write (mount -u -o rw + /mnt). Use your backup program and backup tapes to + recover the data for this filesystem (e.g. restore vrf + /dev/sa0). Unmount the filesystem (e.g. umount + /mnt) Repeat for each filesystem that was + damaged. + + Once your system is running, backup your data onto new tapes. + Whatever caused the crash or data loss may strike again. Another + hour spent now may save you from further distress later. + - Fourth, test the floppies (either boot.flp - and fixit.flp or the two custom bootable - floppies you made in step two.) and backup tapes. Make notes of the - procedure. Store these notes with the bootable floppy, the - printouts and the backup tapes. You will be so distraught when - restoring that the notes may prevent you from destroying your backup - tapes (How? In place of tar xvf /dev/rsa0, you - might accidentally type tar cvf /dev/rsa0 and - over-write your backup tape). +For an added measure of security, make bootable floppies and two - backup tapes each time. Store one of each at a remote location. A - remote location is NOT the basement of the same office building. A - number of firms in the World Trade Center learned this lesson the - hard way. A remote location should be physically separated from - your computers and disk drives by a significant distance. + + * I did not prepare for the Disaster, What Now? - - A Script for Creating a Bootable Floppy - - + +]]> -fdformat -q fd0 -if [ $? -ne 0 ] -then - echo "Bad floppy, please use a new one" - exit 1 -fi + + -# place boot blocks on the floppy -# -disklabel -w -B /dev/fd0c fd1440 + + Network, Memory, and File-Based Filesystems + virtual disks + + disks + virtual + -# -# newfs the one and only partition -# -newfs -t 2 -u 18 -l 1 -c 40 -i 5120 -m 5 -o space /dev/fd0a + Aside from the disks you physically insert into your computer: + floppies, CDs, hard drives, and so forth; other forms of disks + are understood by FreeBSD - the virtual + disks. -# -# mount the new floppy -# -mount /dev/fd0a /mnt + NFS + Coda + + disks + memory + + These include network filesystems such as the Network Filesystem and Coda, memory-based + filesystems such as md and + file-backed filesystems created by vnconfig or + mdconfig. -# -# create required directories -# -mkdir /mnt/dev -mkdir /mnt/bin -mkdir /mnt/sbin -mkdir /mnt/etc -mkdir /mnt/root -mkdir /mnt/mnt # for the root partition -mkdir /mnt/tmp -mkdir /mnt/var + + vnconfig: File-Backed Filesystem + + disks + file-backed + -# -# populate the directories -# -if [ ! -x /sys/compile/MINI/kernel ] -then - cat << EOM -The MINI kernel does not exist, please create one. -Here is an example config file: -# -# MINI -- A kernel to get FreeBSD onto a disk. -# -machine "i386" -cpu "I486_CPU" -ident MINI -maxusers 5 + &man.vnconfig.8; configures and enables vnode pseudo-disk + devices. A vnode is a representation + of a file, and is the focus of file activity. This means that + &man.vnconfig.8; uses files to create and operate a + filesystem. One possible use is the mounting of floppy or CD + images kept in files. -options INET # needed for _tcp _icmpstat _ipstat - # _udpstat _tcpstat _udb -options FFS #Berkeley Fast File System -options FAT_CURSOR #block cursor in syscons or pccons -options SCSI_DELAY=15 #Be pessimistic about Joe SCSI device -options NCONS=2 #1 virtual consoles -options USERCONFIG #Allow user configuration with -c XXX + To mount an existing filesystem image: -config kernel root on da0 swap on da0 and da1 dumps on da0 + + Using vnconfig to mount an Existing Filesystem + Image -device isa0 -device pci0 + &prompt.root; vnconfig vn0 diskimage +&prompt.root; mount /dev/vn0c /mnt + -device fdc0 at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr -device fd0 at fdc0 drive 0 + To create a new filesystem image with vnconfig: -device ncr0 + + Creating a New File-Backed Disk with vnconfig + + &prompt.root; dd if=/dev/zero of=newimage bs=1k count=5k +5120+0 records in +5120+0 records out +&prompt.root; vnconfig -s labels -c vn0 newimage +&prompt.root; disklabel -r -w vn0 auto +&prompt.root; newfs vn0c +Warning: 2048 sector(s) in last cylinder unallocated +/dev/rvn0c: 10240 sectors in 3 cylinders of 1 tracks, 4096 sectors + 5.0MB in 1 cyl groups (16 c/g, 32.00MB/g, 1280 i/g) +super-block backups (for fsck -b #) at: + 32 +&prompt.root; mount /dev/vn0c /mnt +&prompt.root; df /mnt +Filesystem 1K-blocks Used Avail Capacity Mounted on +/dev/vn0c 4927 1 4532 0% /mnt + + -device scbus0 + + md: Memory Filesystem + + disks + memory filesystem + -device sc0 at isa? port "IO_KBD" tty irq 1 vector scintr -device npx0 at isa? port "IO_NPX" irq 13 vector npxintr + md is a simple, efficient means to create memory + filesystems. -device da0 -device da1 -device da2 + Simply take a filesystem you have prepared with, for + example, &man.vnconfig.8;, and: -device sa0 + + md Memory Disk -pseudo-device loop # required by INET -pseudo-device gzip # Exec gzipped a.out's -EOM - exit 1 -fi + &prompt.root; dd if=newimage of=/dev/md0 +5120+0 records in +5120+0 records out +&prompt.root; mount /dev/md0c /mnt +&prompt.root; df /mnt +Filesystem 1K-blocks Used Avail Capacity Mounted on +/dev/md0c 4927 1 4532 0% /mnt + + + + + + + + + Tom + Rhodes + Contributed by + + + + -cp -f /sys/compile/MINI/kernel /mnt + Filesystem Snapshots -gzip -c -best /sbin/init > /mnt/sbin/init -gzip -c -best /sbin/fsck > /mnt/sbin/fsck -gzip -c -best /sbin/mount > /mnt/sbin/mount -gzip -c -best /sbin/halt > /mnt/sbin/halt -gzip -c -best /sbin/restore > /mnt/sbin/restore + + Filesystem Snapshots + Snapshots + + + FreeBSD 5.0 offers a new feature in conjunction with + Soft Updates: Filesystem snapshots. -gzip -c -best /bin/sh > /mnt/bin/sh -gzip -c -best /bin/sync > /mnt/bin/sync + Snapshots allow a user to create an image of specified file + systems and treat this image as a file. + Snapshot files must be created in the filesystem that the + action is performed on, and a user may create no more than 20 + snapshots per filesystem. 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 with the standard &man.rm.1; + command, like regular files. Snapshots may be removed in any order, + however all the used space may not be acquired as another snapshot will + possibly claim some of the blocks that were released. -cp /root/.profile /mnt/root + During initial creation, the flag (see &man.chflags.1; manual page) + is set on to ensure that not even root can write to the snapshot. + The &man.unlink.1; command makes an exception for snapshot files, + however, in which it allows them to be removed even + though they have the flag set, so it is not necessary to + clear the flag before removing a snapshot file. -cp -f /dev/MAKEDEV /mnt/dev -chmod 755 /mnt/dev/MAKEDEV + Snapshots are created with the &man.mount.8; command. To place + a snapshot of /var in the file + /var/snapshot/snap use the following + command: -chmod 500 /mnt/sbin/init -chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt -chmod 555 /mnt/bin/sh /mnt/bin/sync -chmod 6555 /mnt/sbin/restore +&prompt.root; mount -u -o snapshot /var/snapshot/snap /var -# -# create the devices nodes -# -cd /mnt/dev -./MAKEDEV std -./MAKEDEV da0 -./MAKEDEV da1 -./MAKEDEV da2 -./MAKEDEV sa0 -./MAKEDEV pty0 -cd / + Once a snapshot has been created, there are several interesting + things that an administrator can do with them: + + + + Some administrators will use a snapshot file for backup purposes, + where the snapshot can be transfered to a CD or tape. + + + + File integrity, &man.fsck.8; may be ran on the snapshot file. + Assuming that the filesystem was clean when it was mounted, you + should always get a clean (and unchanging) result from running + &man.fsck.8; on the snapshot. This is essentially what the + background &man.fsck.8; process does. + + + + Run the &man.dump.8; utility on the snapshot. + A dump will be returned that is as consistent with the + filesystem as the timestamp of the snapshot. -# -# create minimum filesystem table -# -cat > /mnt/etc/fstab <As of this writing &man.dump.8; has not yet + been changed to set the dumpdates file correctly, so + do not use this feature in production until that fix + is made. + + + + &man.mount.8; the snapshot as a frozen image of the filesystem. + To &man.mount.8; the snapshot + /var/snapshot/snap: -# -# create minimum passwd file -# -cat > /mnt/etc/passwd <&prompt.root; mdconfig -a -t vnode -f /var/snapshot/snap -u 4 +&prompt.root; mount -r /dev/md4 /mnt -cat > /mnt/etc/master.passwd < + -chmod 600 /mnt/etc/master.passwd -chmod 644 /mnt/etc/passwd -/usr/sbin/pwd_mkdb -d/mnt/etc /mnt/etc/master.passwd + You can now walk the hierarchy of your frozen /var + filesystem mounted at /mnt. Everything will + be in the same state it was during the snapshot creation time. + The only exception being that any earlier snapshots will appear + as zero length files. When the use of a snapshot has delimited, + it can be unmounted with: -# -# umount the floppy and inform the user -# -/sbin/umount /mnt -echo "The floppy has been unmounted and is now ready."]]> +&prompt.root; umount /mnt +&prompt.root; mdconfig -d -u 4 - + For more information about and + filesystem snapshots, including technical papers, you can visit + Marshall Kirk McKusick's website at + http://www.mckusick.com + + + + Filesystem Quotas + + accounting + disk space + + disk quotas - - - - After the Disaster + Quotas are an optional feature of the operating system that + allow you to limit the amount of disk space and/or the number of + files a user or members of a group may allocate on a per-file + system basis. This is used most often on timesharing systems where + it is desirable to limit the amount of resources any one user or + group of users may allocate. This will prevent one user or group + of users from consuming all of the available disk space. - The key question is: did your hardware survive? You have been - doing regular backups so there is no need to worry about the - software. + + Configuring Your System to Enable Disk Quotas - If the hardware has been damaged. First, replace those parts - that have been damaged. + Before attempting to use disk quotas, it is necessary to make + sure that quotas are configured in your kernel. This is done by + adding the following line to your kernel configuration + file: - If your hardware is okay, check your floppies. If you are using - a custom boot floppy, boot single-user (type -s - at the boot: prompt). Skip the following - paragraph. - - If you are using the boot.flp and - fixit.flp floppies, keep reading. Insert the - boot.flp floppy in the first floppy drive and - boot the computer. The original install menu will be displayed on - the screen. Select the Fixit--Repair mode with CDROM or - floppy. option. Insert the - fixit.flp when prompted. - restore and the other programs that you need are - located in /mnt2/stand. + options QUOTA - Recover each filesystem separately. + The stock GENERIC kernel does not have + this enabled by default, so you will have to configure, build and + install a custom kernel in order to use disk quotas. Please refer + to for more information on kernel + configuration. - - mount - - root partition - - disklabel - - - newfs - - Try to mount (e.g. mount /dev/da0a - /mnt) the root partition of your first disk. If the - disklabel was damaged, use disklabel to re-partition and - label the disk to match the label that you printed and saved. Use - newfs to re-create the filesystems. Re-mount the root - partition of the floppy read-write (mount -u -o rw - /mnt). Use your backup program and backup tapes to - recover the data for this filesystem (e.g. restore vrf - /dev/sa0). Unmount the filesystem (e.g. umount - /mnt) Repeat for each filesystem that was - damaged. + Next you will need to enable disk quotas in + /etc/rc.conf. This is done by adding the + line: - Once your system is running, backup your data onto new tapes. - Whatever caused the crash or data loss may strike again. Another - hour spent now may save you from further distress later. - + enable_quotas="YES" + + disk quotas + checking + + For finer control over your quota startup, there is an + additional configuration variable available. Normally on bootup, + the quota integrity of each filesystem is checked by the + quotacheck program. The + quotacheck facility insures that the data in + the quota database properly reflects the data on the filesystem. + This is a very time consuming process that will significantly + affect the time your system takes to boot. If you would like to + skip this step, a variable in /etc/rc.conf + is made available for the purpose: -check_quotas="NO" - - * I did not prepare for the Disaster, What Now? + If you are running FreeBSD prior to 3.2-RELEASE, the + configuration is simpler, and consists of only one variable. Set + the following in your /etc/rc.conf: - - -]]> + check_quotas="YES" - - - - - Tapes and FreeBSD + Finally you will need to edit /etc/fstab + to enable disk quotas on a per-filesystem basis. This is where + you can either enable user or group quotas or both for all of your + filesystems. - tape media - The major tape media are the 4mm, 8mm, QIC, mini-cartridge and - DLT. + To enable per-user quotas on a filesystem, add the + userquota option to the options field in the + /etc/fstab entry for the filesystem you want + to enable quotas on. For example: - - 4mm (DDS: Digital Data Storage) + /dev/da1s2g /home ufs rw,userquota 1 2 - - tape media - DDS (4mm) tapes - - - tape media - QIC tapes - - 4mm tapes are replacing QIC as the workstation backup media of - choice. This trend accelerated greatly when Conner purchased Archive, - a leading manufacturer of QIC drives, and then stopped production of - QIC drives. 4mm drives are small and quiet but do not have the - reputation for reliability that is enjoyed by 8mm drives. The - cartridges are less expensive and smaller (3 x 2 x 0.5 inches, 76 x 51 - x 12 mm) than 8mm cartridges. 4mm, like 8mm, has comparatively short - head life for the same reason, both use helical scan. + Similarly, to enable group quotas, use the + groupquota option instead of + userquota. To enable both user and + group quotas, change the entry as follows: - Data throughput on these drives starts ~150kB/s, peaking at ~500kB/s. - Data capacity starts at 1.3 GB and ends at 2.0 GB. Hardware - compression, available with most of these drives, approximately - doubles the capacity. Multi-drive tape library units can have 6 - drives in a single cabinet with automatic tape changing. Library - capacities reach 240 GB. + /dev/da1s2g /home ufs rw,userquota,groupquota 1 2 - The DDS-3 standard now supports tape capacities up to 12 GB (or - 24 GB compressed). + By default, the quota files are stored in the root directory of + the filesystem with the names quota.user and + quota.group for user and group quotas + respectively. See &man.fstab.5; for more + information. Even though the &man.fstab.5; manual page says that + you can specify + an alternate location for the quota files, this is not recommended + because the various quota utilities do not seem to handle this + properly. - 4mm drives, like 8mm drives, use helical-scan. All the benefits - and drawbacks of helical-scan apply to both 4mm and 8mm drives. + At this point you should reboot your system with your new + kernel. /etc/rc will automatically run the + appropriate commands to create the initial quota files for all of + the quotas you enabled in /etc/fstab, so + there is no need to manually create any zero length quota + files. - Tapes should be retired from use after 2,000 passes or 100 full - backups. + In the normal course of operations you should not be required + to run the quotacheck, + quotaon, or quotaoff + commands manually. However, you may want to read their manual pages + just to be familiar with their operation. - - 8mm (Exabyte) + + Setting Quota Limits - tape media - Exabyte (8mm) tapes + disk quotas + limits - 8mm tapes are the most common SCSI tape drives; they are the best - choice of exchanging tapes. Nearly every site has an Exabyte 2 GB 8mm - tape drive. 8mm drives are reliable, convenient and quiet. Cartridges - are inexpensive and small (4.8 x 3.3 x 0.6 inches; 122 x 84 x 15 mm). - One downside of 8mm tape is relatively short head and tape life due to - the high rate of relative motion of the tape across the heads. + Once you have configured your system to enable quotas, verify + that they really are enabled. An easy way to do this is to + run: - Data throughput ranges from ~250kB/s to ~500kB/s. Data sizes start - at 300 MB and go up to 7 GB. Hardware compression, available with - most of these drives, approximately doubles the capacity. These - drives are available as single units or multi-drive tape libraries - with 6 drives and 120 tapes in a single cabinet. Tapes are changed - automatically by the unit. Library capacities reach 840+ GB. + &prompt.root; quota -v + + You should see a one line summary of disk usage and current + quota limits for each filesystem that quotas are enabled + on. - The Exabyte Mammoth model supports 12 GB on one tape - (24 GB with compression) and costs approximately twice as much as - conventional tape drives. + You are now ready to start assigning quota limits with the + edquota command. - Data is recorded onto the tape using helical-scan, the heads are - positioned at an angle to the media (approximately 6 degrees). The - tape wraps around 270 degrees of the spool that holds the heads. The - spool spins while the tape slides over the spool. The result is a - high density of data and closely packed tracks that angle across the - tape from one edge to the other. - + You have several options on how to enforce limits on the + amount of disk space a user or group may allocate, and how many + files they may create. You may limit allocations based on disk + space (block quotas) or number of files (inode quotas) or a + combination of both. Each of these limits are further broken down + into two categories: hard and soft limits. - - QIC - - tape media - QIC-150 - + hard limit + A hard limit may not be exceeded. Once a user reaches his + hard limit he may not make any further allocations on the file + system in question. For example, if the user has a hard limit of + 500 blocks on a filesystem and is currently using 490 blocks, the + user can only allocate an additional 10 blocks. Attempting to + allocate an additional 11 blocks will fail. - QIC-150 tapes and drives are, perhaps, the most common tape drive - and media around. QIC tape drives are the least expensive "serious" - backup drives. The downside is the cost of media. QIC tapes are - expensive compared to 8mm or 4mm tapes, up to 5 times the price per GB - data storage. But, if your needs can be satisfied with a half-dozen - tapes, QIC may be the correct choice. QIC is the - most common tape drive. Every site has a QIC - drive of some density or another. Therein lies the rub, QIC has a - large number of densities on physically similar (sometimes identical) - tapes. QIC drives are not quiet. These drives audibly seek before - they begin to record data and are clearly audible whenever reading, - writing or seeking. QIC tapes measure (6 x 4 x 0.7 inches; 15.2 x - 10.2 x 1.7 mm). Mini-cartridges, which - also use 1/4" wide tape are discussed separately. Tape libraries and - changers are not available. + soft limit + Soft limits, on the other hand, can be exceeded for a limited + amount of time. This period of time is known as the grace period, + which is one week by default. If a user stays over his or her + soft limit longer than the grace period, the soft limit will + turn into a hard limit and no further allocations will be allowed. + When the user drops back below the soft limit, the grace period + will be reset. - Data throughput ranges from ~150kB/s to ~500kB/s. Data capacity - ranges from 40 MB to 15 GB. Hardware compression is available on many - of the newer QIC drives. QIC drives are less frequently installed; - they are being supplanted by DAT drives. + The following is an example of what you might see when you run + the edquota command. When the + edquota command is invoked, you are placed into + the editor specified by the EDITOR environment + variable, or in the vi editor if the + EDITOR variable is not set, to allow you to edit + the quota limits. - Data is recorded onto the tape in tracks. The tracks run along - the long axis of the tape media from one end to the other. The number - of tracks, and therefore the width of a track, varies with the tape's - capacity. Most if not all newer drives provide backward-compatibility - at least for reading (but often also for writing). QIC has a good - reputation regarding the safety of the data (the mechanics are simpler - and more robust than for helical scan drives). + &prompt.root; edquota -u test - Tapes should be retired from use after 5,000 backups. - + Quotas for user test: +/usr: blocks in use: 65, limits (soft = 50, hard = 75) + inodes in use: 7, limits (soft = 50, hard = 60) +/usr/var: blocks in use: 0, limits (soft = 50, hard = 75) + inodes in use: 0, limits (soft = 50, hard = 60) - - XXX* Mini-Cartridge + You will normally see two lines for each filesystem that has + quotas enabled. One line for the block limits, and one line for + inode limits. Simply change the value you want updated to modify + the quota limit. For example, to raise this user's block limit + from a soft limit of 50 and a hard limit of 75 to a soft limit of + 500 and a hard limit of 600, change: - - + /usr: blocks in use: 65, limits (soft = 50, hard = 75) - - DLT - - tape media - DLT - + to: - DLT has the fastest data transfer rate of all the drive types - listed here. The 1/2" (12.5mm) tape is contained in a single spool - cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm). The cartridge has a - swinging gate along one entire side of the cartridge. The drive - mechanism opens this gate to extract the tape leader. The tape leader - has an oval hole in it which the drive uses to "hook" the tape. The - take-up spool is located inside the tape drive. All the other tape - cartridges listed here (9 track tapes are the only exception) have - both the supply and take-up spools located inside the tape cartridge - itself. + /usr: blocks in use: 65, limits (soft = 500, hard = 600) - Data throughput is approximately 1.5MB/s, three times the throughput of - 4mm, 8mm, or QIC tape drives. Data capacities range from 10 GB to 20 GB - for a single drive. Drives are available in both multi-tape changers - and multi-tape, multi-drive tape libraries containing from 5 to 900 - tapes over 1 to 20 drives, providing from 50 GB to 9 TB of - storage. + The new quota limits will be in place when you exit the + editor. - With compression, DLT Type IV format supports up to 70 GB - capacity. + Sometimes it is desirable to set quota limits on a range of + uids. This can be done by use of the option + on the edquota command. First, assign the + desired quota limit to a user, and then run + edquota -p protouser startuid-enduid. For + example, if user test has the desired quota + limits, the following command can be used to duplicate those quota + limits for uids 10,000 through 19,999: - Data is recorded onto the tape in tracks parallel to the direction - of travel (just like QIC tapes). Two tracks are written at once. - Read/write head lifetimes are relatively long; once the tape stops - moving, there is no relative motion between the heads and the - tape. + &prompt.root; edquota -p test 10000-19999 + + For more information see &man.edquota.8;. - AIT + Checking Quota Limits and Disk Usage - tape media - AIT + disk quotas + checking - AIT is a new format from Sony, and can hold up to 50 GB (with - compression) per tape. The tapes contain memory chips which retain an - index of the tape's contents. This index can be rapidly read by the - tape drive to determine the position of files on the tape, instead of - the several minutes that would be required for other tapes. Software - such as SAMS:Alexandria can operate forty or more AIT tape libraries, - communicating directly with the tape's memory chip to display the - contents on screen, determine what files were backed up to which - tape, locate the correct tape, load it, and restore the data from the - tape. + You can use either the quota or the + repquota commands to check quota limits and + disk usage. The quota command can be used to + check individual user or group quotas and disk usage. A user + may only examine his own quota, and the quota of a group he + is a member of. Only the super-user may view all user and group + quotas. The + repquota command can be used to get a summary + of all quotas and disk usage for filesystems with quotas + enabled. - Libraries like this cost in the region of $20,000, pricing them a - little out of the hobbyist market. - + The following is some sample output from the + quota -v command for a user that has quota + limits on two filesystems. - - Using a New Tape for the First Time + Disk quotas for user test (uid 1002): + Filesystem blocks quota limit grace files quota limit grace + /usr 65* 50 75 5days 7 50 60 + /usr/var 0 50 75 0 50 60 - The first time that you try to read or write a new, completely - blank tape, the operation will fail. The console messages should be - similar to: + grace period + On the /usr filesystem in the above + example, this user is currently 15 blocks over the soft limit of + 50 blocks and has 5 days of the grace period left. Note the + asterisk * which indicates that the user is + currently over his quota limit. - sa0(ncr1:4:0): NOT READY asc:4,1 -sa0(ncr1:4:0): Logical unit is in process of becoming ready + Normally filesystems that the user is not using any disk + space on will not show up in the output from the + quota command, even if he has a quota limit + assigned for that filesystem. The option + will display those filesystems, such as the + /usr/var filesystem in the above + example. + - The tape does not contain an Identifier Block (block number 0). - All QIC tape drives since the adoption of QIC-525 standard write an - Identifier Block to the tape. There are two solutions: + + Quotas over NFS + NFS - mt fsf 1 causes the tape drive to write an - Identifier Block to the tape. - - Use the front panel button to eject the tape. + Quotas are enforced by the quota subsystem on the NFS server. + The &man.rpc.rquotad.8; daemon makes quota information available + to the &man.quota.1; command on NFS clients, allowing users on + those machines to see their quota statistics. - Re-insert the tape and dump data to the tape. - - dump will report DUMP: End of tape - detected and the console will show: HARDWARE - FAILURE info:280 asc:80,96. + Enable rpc.rquotad in + /etc/inetd.conf like so: - rewind the tape using: mt rewind. + rquotad/1 dgram rpc/udp wait root /usr/libexec/rpc.rquotad rpc.rquotad - Subsequent tape operations are successful. + Now restart inetd: + + &prompt.root; kill -HUP `cat /var/run/inetd.pid` -