-
- Chapter 6. Restore
-Prev Part I. Installation Next
-
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-
-Chapter 6. Restore
-
-
-Daniel Moore
-
-Original text<dmoore@jeffco.k12.co.us>
-
-Alexandre Oliva
-
-Substantial rewriting
-AMANDA Core Team
-<oliva@dcc.unicamp.br>>
-
-Murf
-
-Corrections and additions<jam@philabs.research.philips.com>
-
-Ralf Fassel
-
-Corrections and additions<ralf@atg.venture.de>
-
-Stefan G. Weichinger
-
-XML-conversion;Updates
-AMANDA Core Team
-<sgw@amanda.org>
-This document describes how to restore files backed up with Amanda either with
-or without Amanda tools.
-All these cases assume you're trying to restore a complete disk, that is,
-you've replaced the lost disk with a new one, or created a new filesystem on
-it. Tweaking with the arguments to restore (not amrestore), you will be able to
-restore individual files.
-Also, this text does not cover amrecover, a program that provides a text user
-interface similar to interactive restore (restore -i), but it allows you to
-select individual files to recover and automatically determines the tapes where
-they were stored. The backups must be performed with the `index' option enabled
-for this to work.
-I considered the following cases.
-The server machine (machine Aaron) runs solaris, the client machine (machine
-Barney) runs sunos.
-
- 1. Client machine fails, non-system critical.
- Example: /home fails on Barney.
- First, use amadmin to find the tapes most recently used to backup the
- partition.
-
- amadmin <config> info Barney '/home$'
-
- Current info for Barney /home:
- Stats: dump rates (kps), Full: 41.1, 33.1, 38.8
- Incremental: 9.5, 2.1, 24.7
- compressed size, Full: 63.1%, 54.0%, 52.9%
- Incremental: 43.7%, 15.5%, 47.8%
- Dumps: lev datestmp tape file origK compK secs
- 0 19971223 Barney01 16 329947 208032 5060
- 1 19980108 Barney16 8 1977 864 91
- 2 19971222 Barney06 7 1874 672 83
- 3 19970926 Barney03 11 12273 3040 211
-
- This tells us that we will need two tapes to do a full restore (Barney01,
- Barney16). Note that, even if Barney06 and Barney03 are listed, they are
- actually older than the full backup, so they should not be used to restore
- any data.
- Log into Barney. Cd to the /home directory. Insert the tape with the level
- 0 dump on it into the tape drive of Aaron.
- Become super-user in the client host and run (replace <amanda> with the
- username under which amanda runs):
-
- rsh -n -l <amanda> Aaron amrestore -p /dev/rmt/0cn Barney '/home\$' |
- restore -ivbf 2 -
-
- This requires client root to have login access to <amanda>@Aaron, with a
- .rhosts entry (.amandahosts won't do). If you use ssh, you may be able to
- type a password in order to be authenticated. Another alternative is to
- start the operation in the server, and rsh to the client. You should be
- the amanda user or root in the tape server and run:
-
- amrestore -p /dev/rmt/0cn Barney '/home$' |
- rsh Barney -l root /usr/etc/restore -ivbf 2 -
-
- If you don't want to use rsh at all, you may run:
-
- amrestore /dev/rmt/0cn Barney '/home$'
-
- This should create a file whose name contains the hostname, directory
- name, dump level and dump date of the backup. Now you have to move this
- file to the client somehow: you may use NFS, rcp, ftp, floppy disks :-),
- whatever. Suppose you rename that file to `home.0'. Then, on the client,
- you should become root and run:
-
- restore -ivbf 2 home.0
-
- Repeat one of these steps, incrementing the level of the dump, until there
- are no more available backups.
- 2. Client machine fails, system critical disk.
- Example: / fails on Barney.
- First of all, boot off the CD, and reinstall the system critical
- partition, restoring it to vendor supplied state. Then, go through all of
- Scenario 1.
- 3. Server machine fails, non-system critical, non-Amanda disk.
- Proceed just as described in Scenario 1. However, you won't have to go
- through the rsh process, because you can just use amrestore to replace the
- lost data directly.
- 4. Server machine fails, system critical, non-Amanda disk.
- Example: / on Aaron
- First of all, boot off the CD, and reinstall the system critical
- partition, restoring it to vendor supplied state.
- Then, follow steps in Scenario 3.
- 5. Server machine fails, non-system critical, Amanda disk, with db.
- Example: /opt on Aaron
- If the disk that contains the Amanda database is toast, then you need to
- rebuild the database. The easiest way to do it is to take the text file
- that you had mailed to you via the 'amadmin export' command, and import
- via the 'amadmin import' command. Then you should be able to follow the
- steps outlined in Scenario 4.
- Note that Amanda does not mail the exported database automatically; you
- may add this to the crontab entry that runs amanda.
- Maybe it's a good idea to print out the text files as well and store the
- last 2 dumpcycles worth of paper (the disc text files might have got
- toasted as well). From the paper you still are able to reconstruct where
- your discs are.
- 6. Server machine fails, non-system critical, Amanda disk, with binaries.
- Example: /usr/local on Aaron
- This is where things get hairy. If the disk with the amanda binaries on it
- is toast, you have three options.
-
- i. reinstall the Amanda binaries from another tape, on which you have
- conveniently backed up the binaries within the last couple of weeks
- (not using Amanda).
- ii. recompile Amanda, making sure not to overwrite your db files.
- iii. use dd to read Amanda formatted tapes. This is the option I am going
- to explore most fully, because this seems the most likely to occur.
-
- a. Find out the device name used by Amanda, by looking in
- amanda.conf. Turns out to be /dev/rmt/0cn for this system.
- If amanda.conf isn't at hand: this must be a non-rewinding tape
- device specifier (which I believe the trailing `n' stands for).
- b. Look over the copy of the output of 'amadmin <config> export',
- and find out which tapes /usr/local was backed up on.
- c. Grab the tapes that /opt was backed up on, and stick the level 0
- into the drive. cd to /usr/local.
- d. Skip the first record, which is just the tape header, by using
- the appropriate tape command.
-
- mt -f /dev/rmt/0cn fsf 1
-
- e. Now you want to start looking for /usr/local on this tape.
-
- dd if=/dev/rmt/0cn bs=32k skip=1 | gzip -d | /usr/sbin/
- ufsrestore -ivf -
-
- This command gives us an interactive restore of this record,
- including telling us what partition, what host, and what level
- the backup was. The gzip -d portion of the pipe can be omitted
- if there was no compression.
- f. If you don't find /usr/local on the first try, quit ufsrestore,
- and move forward one record.
-
- mt -f /dev/rmt/0cn fsf 1
-
- and try the dd/restore command shown above. Do this until you
- find /opt on the disk.
- Another possibility: quick and dirty tape index in case you
- don't know which partition /usr/local was on: (from
- <ralf@atg.venture.de>)
-
- #!/bin/sh
- TAPEDEV=/dev/nrtape
- while mt -f $TAPEDEV fsf 1 ; do
- dd if=$TAPEDEV bs=32k count=1 | head -1
- sleep 1
- done
-
- Example output:
-
- Amanda: FILE 19971220 uri /root-sun4 lev 1 comp .gz program
- DUMP
- Amanda: FILE 19971220 uri /misc lev 1 comp .gz program DUMP
- Amanda: FILE 19971220 uri / lev 1 comp .gz program DUMP
-
- g. Restore the Amanda binaries (what else do you need??), and then
- bail out of ufsrestore. You can use amrestore, as in Scenario 3.
-
-
-
-
-Note
-
-Refer to http://www.amanda.org/docs/restore.html for the current version of
-this document.
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