From d37187a4063b466c8fec3cfeb3647284da58c65d Mon Sep 17 00:00:00 2001 From: Stelian Pop Date: Tue, 2 Oct 2001 09:32:54 +0000 Subject: [PATCH] Added howto from Patrick Walsh --- examples/howto/ultra-mini-howto | 244 ++++++++++++++++++++++++++++++++ 1 file changed, 244 insertions(+) create mode 100644 examples/howto/ultra-mini-howto diff --git a/examples/howto/ultra-mini-howto b/examples/howto/ultra-mini-howto new file mode 100644 index 0000000..6c2c8ab --- /dev/null +++ b/examples/howto/ultra-mini-howto @@ -0,0 +1,244 @@ +Stelian, + + I just got dump running on my system backing up a handful of unix +servers and at the end of it I wrote a quick and dirty document that lays +out the answers to some of the questions that I had. I don't want to +maintain it or get a flood of e-mail from people asking for help on it, so I +signed it, but intentionally didn't put an e-mail address. + + You are welcome to make this prettier, totally discard it, or put it up +on the web page. I hope it is accurate and relieves some of the common +questions from the list. + +..Patrick + + + + +Dump/Restore Ultra-Mini-FAQ + +Disclaimer: I am not an expert in dump/restore. In fact, +I'm a newbie. But I've been picking things up as I +implement it here and I wanted to pass some of those +things along in the form of a very basic HOWTO. + +-Patrick Walsh + +1) Introduction/ Non-rewinding device +2) Dump command line +3) Sending 2 or more filesystems to a tape +4) Compressing dumps on the fly +5) The "nodump" file and directory attribute. +6) Restoring your dumps (including compressed). +7) How to confirm a backup +8) Example backup script + + 1) Introduction/ Non-rewinding device + +You use dump to backup to a file or a tape device. If +you're backing up to a tape device, then the first thing +you need to understand is that there are two devices +that refer to your tape drive. There is the "rewinding" +device and the "non-rewinding" device. + +I wish I could tell you an easy way to figure out what +your device names are, but I don't know one. On my +local box I had a /dev/tape device that linked to +/dev/st0. It turns out that /dev/st0 is my "rewinding" +tape drive. If I write to this device it will always +rewind before starting to write. This means that if +you try to dump two filesystems, only the second one +will be stored. If your tape device is /dev/st0, like +mine, then your non-rewinding tape device is probably +/dev/nst0. + +Anyway, through the rest of this I will refer to $TAPE +and $RWTAPE. $TAPE is the non-rewinding device (in my +case /dev/nst0) and $RWTAPE is the rewinding tape (in my +case /dev/st0 and /dev/tape). $FS is the filesystem you +are backing up, such as /dev/hda1. + + 2) What options should I use? + +Use the man page to figure out what options to send +to dump. I use "dump 0uanf $TAPE $FS". + + u=update /etc/dumpdates after a successful dump + a=auto-size -- bypass all tape length calculations and + write until eof + n=notify 'operators' group when dump needs attention + f=backup to file or device specified, or - for stdout + + 3) You want to send two or more filesystems to the tape. + +OK, rewind using the mt command, then dump multiple times +to the non-rewinding device, and you're done: + +mt -f $TAPE rewind +dump 0uanf $TAPE $FS1 +dump 0uanf $TAPE $FS2 +etc. + +Check the man page of mt if you want to know how to eject +the tape or retension it or anything. + + 4) You want to compress your dumps on the fly. No +problem. Send your backup to STDOUT and manipulate it +from there. It's easier if you're sending your output to +the hard drive: + +dump 0uanf - $FS | gzip -c > /backup/outfile.dump.gz + +You want that to be written to the tape on the fly? Try +this: + +mt -f $TAPE rewind +dump 0uanf - $FS |gzip -c |dd if=- of=$TAPE + +[ You can also use the -z or -J options of dump in the + recent versions to enable internal compression - stelian ] + + 5) You read the man page and you're wondering what the +heck a "nodump" flag is. For example, how can you get +dump to stop backing up /tmp or ~/.netscape/cache. You +have two options: either exclude the inode in your dump +command, or flag the files and directories with the +"nodump" flag. To flag /tmp, for example, do this: + +chattr -R +d /tmp + +Want more details? Try 'man chattr' and 'man lsattr'. + + 6) You want to know how to restore your backup. + +Read the restore man page. But barring that, the easy way +is to use restore in interactive mode. If you have three +filesystems on one tape and you want to restore files from +the second one, you need to do this: + +mt -f $TAPE rewind +mt -f $TAPE fsf 1 # skip forward one file +restore -if $TAPE + +OK, suppose now that you used the commands in section 4 to +compress the dump file before it was written to disk. Use +this command: + +mt -f $TAPE rewind +mt -f $TAPE fsf 1 +dd if=$TAPE of=- |gzip -dc |restore -rf - + +Obviously if you dumped to a file instead of a tape it is +much easier: + +gzip -dc $filename |restore -rf - + + 7) How to confirm your backup + + Check out the restore man page and read up on the -C option. + + 8) That about sums up my knowledge on the matter, but +I feel better having written something for other people to +look at so it doesn't take them quite so long to learn the +things I did. I've included my backup script below. +There are much better ones floating around, so go find +someone else's and use theirs if mine won't work for you +or you don't understand it. + + +#!/bin/csh +# System backup script for NARNIA + +# This is a script that will backup the entire hard drive +# to the NT server (not my choice) \\fs1. +# +# On each Sunday night, a full backup will be made +# of the hard drive and each day of the week thereafter an incremental +# backup will be made that captures only those changes since the night +# before. +# Each full backup will be sent to the local tape as well as to the +# NT machine. +# +# The files will be stored in partition-specific files with integer +# endings that specify the day of the week they were saved. Files +# with zero on the end will always be full backups. + +# Dump options: +# a=auto-size -- bypass all tape length calculations and write until eof +# f=write the backup to file or device specified or - for stdout +# n=notify operators group when dump needs attention +# u=update /etc/dumpdates after a successful dump + +# Set variables that control the script. +setenv MOUNTPOINT '/root/fs1backup' +setenv OUTDIR '/root/fs1backup/narnia' +setenv TAPE '/dev/nst0' # non-rewinding tape + +# Auto-set variable that determines level of backup. +setenv DAY `date +'%w'` + +# Mount the backup partition to /root/fs1backup +/usr/bin/smbmount \\\\fs1\\backup $MOUNTPOINT -o +"username=uname,password=pword" + +# Delete files created on this day last week +rm -f $OUTDIR/*$DAY.dump.gz + +# Do the actual backing up, one filesystem at a time. + +# /dev/hda1 = /boot +/sbin/dump $DAY'uanf' - /dev/hda1 | gzip -c >$OUTDIR/boot-$DAY.dump.gz + +# /dev/hda2 = / +/sbin/dump $DAY'uanf' - /dev/hda2 | gzip -c >$OUTDIR/root-$DAY.dump.gz + +# /dev/hda3 = /usr +/sbin/dump $DAY'uanf' - /dev/hda3 | gzip -c >$OUTDIR/usr-$DAY.dump.gz + +# /dev/hdb2 = /u1 +/sbin/dump $DAY'uanf' - /dev/hdb2 | gzip -c >$OUTDIR/u1-$DAY.dump.gz + + +# OK, presumably everything is now backed up to \\fs1. On level 0 +# dumps, lets backup to the local drive too. +if ($DAY == 0) then + mt -f $TAPE retension + foreach i ($OUTDIR/*0.dump.gz) + dd if=$i of=$TAPE + end + mt -f $TAPE rewind +endif + + +# Unmount the backup partition, not needed outside of script +umount /root/fs1backup + +# Explicitly free up the temporary variables +unsetenv DAY +unsetenv MOUNTPOINT +unsetenv OUTDIR +unsetenv TAPE + + +# RESTORE DIRECTIONS: +# If from tape: +# dd if=$TAPE of=- | gzip -dc | restore -rf - +# or dd if=$TAPE |gzip -dc |restore -rf - +# +# Note: must queue tape to proper position first. This +# is done by first rewinding then advancing to the proper +# file. The order that files are written to tape is +# *probably* 0=/boot 1=/ 2=/usr 3=/u1 +# +# Use mt to skip between them: +# mt -f $TAPE rewind +# restore -if $TAPE #now restoring /boot, probably +# mt -f $TAPE fsf 1 +# restore -if $TAPE #now restoring / +# mt -f $TAPE fsf 1 +# restore -if $TAPE #now restoring /usr +# #etc. +# +# Otherwise: +# gzip -dc $filename | restore -rf - + -- 2.39.5