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diff --git a/en_US.ISO8859-1/books/handbook/backups/chapter.sgml b/en_US.ISO8859-1/books/handbook/backups/chapter.sgml deleted file mode 100644 index 36eb30da9d..0000000000 --- a/en_US.ISO8859-1/books/handbook/backups/chapter.sgml +++ /dev/null @@ -1,732 +0,0 @@ -<!-- - The FreeBSD Documentation Project - - $FreeBSD: doc/en_US.ISO_8859-1/books/handbook/backups/chapter.sgml,v 1.24 2000/06/13 18:05:34 jim Exp $ ---> - -<chapter id="backups"> - <title>Backups</title> - - <sect1> - <title>Synopsis</title> - - <para>The following chapter will cover methods of backing up data, and - the programs used to create those backups. If you would like to - contribute something to this section, send it to the &a.doc;.</para> - </sect1> - - <sect1 id="backups-tapebackups"> - <title>Tape Media</title> - - <para>The major tape media are the 4mm, 8mm, QIC, mini-cartridge and - DLT.</para> - - <sect2 id="backups-tapebackups-4mm"> - <title>4mm (DDS: Digital Data Storage)</title> - - <para>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.</para> - - <para>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.</para> - - <para>The DDS-3 standard now supports tape capacities up to 12GB (or - 24GB compressed).</para> - - <para>4mm drives, like 8mm drives, use helical-scan. All the benefits - and drawbacks of helical-scan apply to both 4mm and 8mm drives.</para> - - <para>Tapes should be retired from use after 2,000 passes or 100 full - backups.</para> - </sect2> - - <sect2 id="backups-tapebackups-8mm"> - <title>8mm (Exabyte)</title> - - <para>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.</para> - - <para>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.</para> - - <para>The Exabyte <quote>Mammoth</quote> model supports 12GB on one tape - (24MB with compression) and costs approximately twice as much as - conventional tape drives.</para> - - <para>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.</para> - </sect2> - - <sect2 id="backups-tapebackups-qic"> - <title>QIC</title> - - <para>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 - <emphasis>most</emphasis> 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). <link - linkend="backups-tapebackups-mini">Mini-cartridges</link>, which - also use 1/4" wide tape are discussed separately. Tape libraries and - changers are not available.</para> - - <para>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.</para> - - <para>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).</para> - - <para>Tapes should be retired from use after 5,000 backups.</para> - </sect2> - -<![ %not.published; [ - - <sect2 id="backups-tapebackups-mini"> - <title>* Mini-Cartridge</title> - - <para></para> - </sect2> - -]]> - - <sect2 id="backups-tapebackups-dlt"> - <title>DLT</title> - - <para>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.</para> - - <para>Data throughput is approximately 1.5MB/s, three times the throughput of - 4mm, 8mm, or QIC tape drives. Data capacities range from 10GB to 20GB - 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 50GB to 9TB of - storage.</para> - - <para>With compression, DLT Type IV format supports up to 70GB - capacity.</para> - - <para>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.</para> - </sect2> - - <sect2> - <title id="backups-tapebackups-ait">AIT</title> - - <para>AIT is a new format from Sony, and can hold up to 50GB (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 where backed up to which - tape, locate the correct tape, load it, and restore the data from the - tape.</para> - - <para>Libraries like this cost in the region of $20,000, pricing them a - little out of the hobbyist market.</para> - </sect2> - - <sect2> - <title>Using a New Tape for the First Time</title> - - <para>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:</para> - - <screen>sa0(ncr1:4:0): NOT READY asc:4,1 -sa0(ncr1:4:0): Logical unit is in process of becoming ready</screen> - - <para>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:</para> - - <para><command>mt fsf 1</command> causes the tape drive to write an - Identifier Block to the tape.</para> - - <para>Use the front panel button to eject the tape.</para> - - <para>Re-insert the tape and &man.dump.8; data to the tape.</para> - - <para>&man.dump.8; will report <literal>DUMP: End of tape - detected</literal> and the console will show: <literal>HARDWARE - FAILURE info:280 asc:80,96</literal></para> - - <para>rewind the tape using: <command>mt rewind</command></para> - - <para>Subsequent tape operations are successful.</para> - </sect2> - </sect1> - - <sect1 id="backup-programs"> - <title>Backup Programs</title> - - <para>The three major programs are - &man.dump.8;, - &man.tar.1;, - and - &man.cpio.1;.</para> - - <sect2> - <title>Dump and Restore</title> - - <para>&man.dump.8; and &man.restore.8; are the traditional Unix backup - programs. 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. &man.dump.8; backs up devices, entire - filesystems, not parts of a filesystem and not directory trees that - span more than one filesystem, using either soft links &man.ln.1; or - mounting one filesystem onto another. &man.dump.8; does not write - files and directories to tape, but rather writes the data blocks that - are the building blocks of files and directories. &man.dump.8; has - quirks that remain from its early days in Version 6 of ATT 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.</para> - - <para>&man.rdump.8; and &man.rrestore.8; backup data across the network - to a tape drive attached to another computer. Both programs rely upon - &man.rcmd.3; and &man.ruserok.3; to access the remote tape drive. - Therefore, the user performing the backup must have - <literal>rhosts</literal> access to the remote computer. The - arguments to &man.rdump.8; and &man.rrestore.8; must suitable to use - on the remote computer. (e.g. When <command>rdump</command>'ing from - a FreeBSD computer to an Exabyte tape drive connected to a Sun called - <hostid>komodo</hostid>, use: <command>/sbin/rdump 0dsbfu 54000 13000 - 126 komodo:/dev/nrsa8 /dev/rda0a 2>&1</command>) Beware: there - are security implications to allowing <literal>rhosts</literal> - commands. Evaluate your situation carefully.</para> - </sect2> - - <sect2> - <title>Tar</title> - - <para>&man.tar.1; also dates back to Version 6 of ATT Unix (circa 1975). - &man.tar.1; operates in cooperation with the filesystem; &man.tar.1; - writes files and directories to tape. &man.tar.1; does not support the - full range of options that are available from &man.cpio.1;, but - &man.tar.1; does not require the unusual command pipeline that - &man.cpio.1; uses.</para> - - <para>Most versions of &man.tar.1; do not support backups across the - network. The GNU version of &man.tar.1;, which FreeBSD utilizes, - supports remote devices using the same syntax as &man.rdump.8;. To - &man.tar.1; to an Exabyte tape drive connected to a Sun called - <hostid>komodo</hostid>, use: <command>/usr/bin/tar cf - komodo:/dev/nrsa8 . 2>&1</command>. For versions without remote - device support, you can use a pipeline and &man.rsh.1; to send the - data to a remote tape drive.</para> - - <screen>&prompt.root; <userinput>tar cf - . | rsh <replaceable>hostname</replaceable> dd of=<replaceable>tape-device</replaceable> obs=20b</userinput></screen> - - <para>If you're worried about the security of backing over a network - you should use the &man.ssh.1; command instead of &man.rsh.1;.</para> - </sect2> - - <sect2> - <title>Cpio</title> - - <para>&man.cpio.1; is the original Unix file interchange tape program - for magnetic media. &man.cpio.1; has options (among many others) to - perform byte-swapping, write a number of different archives format, - and pipe the data to other programs. This last feature makes - &man.cpio.1; and excellent choice for installation media. - &man.cpio.1; does not know how to walk the directory tree and a list - of files must be provided through <filename>stdin</filename>.</para> - - <para>&man.cpio.1; does not support backups across the network. You can - use a pipeline and &man.rsh.1; to send the data to a remote tape - drive. (XXX add an example command)</para> - </sect2> - - <sect2> - <title>Pax</title> - - <para>&man.pax.1; is IEEE/POSIX's answer to &man.tar.1; and - &man.cpio.1;. Over the years the various versions of &man.tar.1; - and &man.cpio.1; have gotten slightly incompatible. So rather than - fight it out to fully standardize them, POSIX created a new archive - utility. &man.pax.1; attempts to read and write many of the various - &man.cpio.1; and &man.tar.1; formats, plus new formats of its own. - Its command set more resembles &man.cpio.1; than &man.tar.1;.</para> - </sect2> - - <sect2 id="backups-programs-amanda"> - <title>Amanda</title> - - <para><ulink url="../ports/misc.html#amanda-2.4.0">Amanda</ulink> - (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 network communications with the Amanda server. A common problem - at locations with a number of large disks is 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.</para> - - <para>The configuration file provides fine control 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.</para> - </sect2> - - <sect2> - <title>Do Nothing</title> - - <para><quote>Do nothing</quote> 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!</para> - - <para>If your time and your data is worth little to nothing, then - <quote>Do nothing</quote> 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.</para> - - <para><quote>Do nothing</quote> is the correct backup method for - <filename>/usr/obj</filename> and other directory trees that can be - exactly recreated by your computer. An example is the files that - comprise these handbook pages-they have been generated from - <acronym>SGML</acronym> input files. Creating backups of these - <acronym>HTML</acronym> files is not necessary. The - <acronym>SGML</acronym> source files are backed up regularly.</para> - </sect2> - - <sect2> - <title>Which Backup Program is Best?</title> - - <para>&man.dump.8; <emphasis>Period.</emphasis> 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 &man.dump.8;. 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 that - 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 <ulink - url="http://reality.sgi.com/zwicky_neu/testdump.doc.html">torture-testing - Backup and Archive Programs</ulink>.</para> - </sect2> - - <sect2> - <title>Emergency Restore Procedure</title> - - <sect3> - <title>Before the Disaster</title> - - <para>There are only four steps that you need to perform in - preparation for any disaster that may occur.</para> - - <para>First, print the disklabel from each of your disks - (<command>e.g. disklabel da0 | lpr</command>), your filesystem table - (<filename>/etc/fstab</filename>) and all boot messages, - two copies of - each.</para> - - <para>Second, determine that the boot and fix-it floppies - (<filename>boot.flp</filename> and <filename>fixit.flp</filename>) - 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.</para> - - <para>Otherwise, you have to create two custom bootable floppies which - has a kernel that can mount your all of your disks and access your - tape drive. These floppies must contain: - &man.fdisk.8;, &man.disklabel.8;, &man.newfs.8;, &man.mount.8;, and - whichever backup program you use. These programs must be statically - linked. If you use &man.dump.8;, the floppy must contain - &man.restore.8;.</para> - - <para>Third, create backup tapes regularly. Any changes that you make - after your last backup may be irretrievably lost. Write-protect the - backup tapes.</para> - - <para>Fourth, test the floppies (either <filename>boot.flp</filename> - and <filename>fixit.flp</filename> 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 <command>tar xvf /dev/rsa0</command>, you - might accidently type <command>tar cvf /dev/rsa0</command> and - over-write your backup tape).</para> - - <para>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.</para> - - <para>An example script for creating a bootable floppy:</para> - - <programlisting> -<![ CDATA [#!/bin/sh -# -# create a restore floppy -# -# format the floppy -# -PATH=/bin:/sbin:/usr/sbin:/usr/bin - -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/rfd0c fd1440 - -# -# newfs the one and only partition -# -newfs -t 2 -u 18 -l 1 -c 40 -i 5120 -m 5 -o space /dev/rfd0a - -# -# mount the new floppy -# -mount /dev/fd0a /mnt - -# -# 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 - -# -# 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 on onto a disk. -# -machine "i386" -cpu "I486_CPU" -ident MINI -maxusers 5 - -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 - -config kernel root on da0 swap on da0 and da1 dumps on da0 - -controller isa0 -controller pci0 - -controller fdc0 at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr -disk fd0 at fdc0 drive 0 - -controller ncr0 - -controller scbus0 - -device sc0 at isa? port "IO_KBD" tty irq 1 vector scintr -device npx0 at isa? port "IO_NPX" irq 13 vector npxintr - -device da0 -device da1 -device da2 - -device sa0 - -pseudo-device loop # required by INET -pseudo-device gzip # Exec gzipped a.out's -EOM - exit 1 -fi - -cp -f /sys/compile/MINI/kernel /mnt - -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 - -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 <<EOM -/dev/fd0a / ufs rw 1 1 -EOM - -# -# create minimum passwd file -# -cat > /mnt/etc/passwd <<EOM -root:*:0:0:Charlie &:/root:/bin/sh -EOM - -cat > /mnt/etc/master.passwd <<EOM -root::0:0::0:0:Charlie &:/root:/bin/sh -EOM - -chmod 600 /mnt/etc/master.passwd -chmod 644 /mnt/etc/passwd -/usr/sbin/pwd_mkdb -d/mnt/etc /mnt/etc/master.passwd - -# -# umount the floppy and inform the user -# -/sbin/umount /mnt -echo "The floppy has been unmounted and is now ready."]]></programlisting> - </sect3> - - <sect3> - <title>After the Disaster</title> - - <para>The key question is: did your hardware survive? You have been - doing regular backups so there is no need to worry about the - software.</para> - - <para>If the hardware has been damaged. First, replace those parts - that have been damaged.</para> - - <para>If your hardware is okay, check your floppies. If you are using - a custom boot floppy, boot single-user (type <literal>-s</literal> - at the <prompt>boot:</prompt> prompt). Skip the following - paragraph.</para> - - <para>If you are using the <filename>boot.flp</filename> and - <filename>fixit.flp</filename> floppies, keep reading. Insert the - <filename>boot.flp</filename> floppy in the first floppy drive and - boot the computer. The original install menu will be displayed on - the screen. Select the <literal>Fixit--Repair mode with CDROM or - floppy.</literal> option. Insert the - <filename>fixit.flp</filename> when prompted. - <command>restore</command> and the other programs that you need are - located in <filename>/mnt2/stand</filename>.</para> - - <para>Recover each filesystem separately.</para> - - <para>Try to &man.mount.8; (e.g. <command>mount /dev/da0a - /mnt</command>) the root partition of your first disk. If the - disklabel was damaged, use &man.disklabel.8; to re-partition and - label the disk to match the label that your printed and saved. Use - &man.newfs.8; to re-create the filesystems. Re-mount the root - partition of the floppy read-write (<command>mount -u -o rw - /mnt</command>). Use your backup program and backup tapes to - recover the data for this filesystem (e.g. <command>restore vrf - /dev/sa0</command>). Unmount the filesystem (e.g. <command>umount - /mnt</command>) Repeat for each filesystem that was - damaged.</para> - - <para>Once your system is running, backup your data onto new tapes. - Whatever caused the crash or data loss may strike again. An another - hour spent now, may save you from further distress later.</para> - </sect3> - -<![ %not.published; [ - - <sect3> - <title>* I did not prepare for the Disaster, What Now?</title> - - <para></para> - </sect3> -]]> - - </sect2> - </sect1> - - <sect1 id="backups-floppybackups"> - <title>What about Backups to Floppies?</title> - - <sect2 id="floppies-using"> - <title>Can I use floppies for backing up my data?</title> - - <para>Floppy disks are not really a suitable media for - making backups as:</para> - - <itemizedlist> - <listitem> - <para>The media is unreliable, especially over long periods of - time</para> - </listitem> - - <listitem> - <para>Backing up and restoring is very slow</para> - </listitem> - - <listitem> - <para>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).</para> - </listitem> - </itemizedlist> - - <para>However, if you have no other method of backing up your data then - floppy disks are better than no backup at all.</para> - - <para>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.</para> - </sect2> - - <sect2 id="floppies-creating"> - <title>So how do I backup my data to floppies?</title> - - <para>The best way to backup to floppy disk is to use - &man.tar.1; with the <option>-M</option> (multi volume) option, which - allows backups to span multiple floppies.</para> - - <para>To backup all the files in the current directory and sub-directory - use this (as root):</para> - - <screen>&prompt.root; <userinput>tar Mcvf /dev/rfd0 *</userinput></screen> - - <para>When the first floppy is full &man.tar.1; will prompt you to - insert the next volume (because &man.tar.1; is media independent it - refers to volumes. In this context it means floppy disk)</para> - - <screen>Prepare volume #2 for /dev/rfd0 and hit return:</screen> - - <para>This is repeated (with the volume number incrementing) until all - the specified files have been archived.</para> - </sect2> - - <sect2 id="floppies-compress"> - <title>Can I compress my backups?</title> - - <para>Unfortunately, &man.tar.1; will not allow the - <option>-z</option> option to be used for multi-volume archives. - You could, of course, &man.gzip.1; all the files, &man.tar.1; them to - the floppies, then &man.gunzip.1; the files again!</para> - </sect2> - - <sect2 id="floppies-restoring"> - <title>How do I restore my backups?</title> - - <para>To restore the entire archive use:</para> - - <screen>&prompt.root; <userinput>tar Mxvf /dev/rfd0</userinput></screen> - - <para>To restore only specific files you can either start with the first - floppy and use:</para> - - <screen>&prompt.root; <userinput>tar Mxvf /dev/rfd0 <replaceable>filename</replaceable></userinput></screen> - - <para>&man.tar.1; will prompt you to insert subsequent floppies until it - finds the required file.</para> - - <para>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 &man.tar.1; will warn you that it cannot restore it, - even if you have not asked it to!</para> - </sect2> - </sect1> -</chapter> - -<!-- - Local Variables: - mode: sgml - sgml-declaration: "../chapter.decl" - sgml-indent-data: t - sgml-omittag: nil - sgml-always-quote-attributes: t - sgml-parent-document: ("../book.sgml" "part" "chapter") - End: ---> |