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- Chapter 3. Excluding
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-
-Chapter 3. Excluding
-
-
-Andrew Hall
-
-Original text
-
-Stefan G. Weichinger
-
-XML-conversion;Updates
-AMANDA Core Team
-<sgw@amanda.org>
-Table of Contents
-
-
- Introduction
-
- Please_Read
-
- Before_We_Begin
-
- Choosing_an_exclude_mechanism
-
-
- Exclude_Mechanisms
-
-
- Expression
-
- Wildcard_Expansion
-
- Troubleshooting
-
-
- Broken_gnutar?
-
- The_ps_command_is_your_friend.
-
-
-
- Introduction
-
-There are times when data needs to be excluded from a backup. When these times
-arise be confident that Amanda has this capability. (Actually it's not Amanda,
-it's tar.) There are three ways of excluding data in an Amanda backup:
-
-* Exclude an individual item explicitly in the dumptype
-* Utilize an "Exclude List"
-* Do not include the data in the disklist
-
-This document is based on Amanda 2.4.2 and some of this might not work with
-older versions. This was compiled from my personal experience and with help
-from the members of the amanda-users mailing list (mailto://amanda-
-users@amanda.org) when I was originally setting this up, to whom I wish to
-thank for all of their support.
-
- Please Read
-
-As far as I am able to tell the only way to exclude files or directories with
-Amanda is to use GNU-tar as the dump program (others?). The file system dump
-programs provided with unix systems (e.g. dump, ufsdump) get data at a raw
-drive level and generally do not allow exclusion of specific files or
-directories.
-The GNU version of tar, (GNU-tar or gtar), reads its data at a file system, (or
-higher), level and does include the option to exclude specific files and/or
-directories. It should be mentioned here that tar will change the access times
-on files. Tar has the ability to preserve the access times however, doing so
-effectively disables incremental backups since resetting the access time alters
-the inode change time, which in turn causes the file to look like it needs to
-be archived again.
-The only exception that I am aware of is to just not include the data in
-question in the disklist. This option may not be suitable for everyone's needs
-and can confuse the issue some, so I have elected to include this mechanism in
-its own section named Do_not_include_the_data_in_the_disklist.
-For the purpose of this document an Amanda backup configuration named "exclude-
-test" will be used. The machine that contains the tape drive which receives
-data to be archived will be referred to as "SERVER". The machine that data is
-being archived from will be referred to as "CLIENT". These two systems are
-usually different machines but are not required to be, and may be the same
-machine. Parts of this setup are on the server and some are on the client.
-
-Note
-
-When Amanda attempts to exclude a file or directory it does so relative to the
-area being archived. For example if /var is in your disklist and you want to
-exclude /var/log/somefile, then your exclude file would contain ./log/somefile.
-You may use one exclude file in multiple dumptypes without any restriction.
-
- Before We Begin
-
-The first step that should be taken is to verify that backups are currently
-working. Connect to SERVER and run amcheck as your Amanda user, to verify that
-there are no errors in the current setup.
-
- $ amcheck -cl CLIENT
-
-Output should look something like below for success:
-
- Amanda Tape Server Host Check
- -----------------------------
-
- /path/to/holding-disk: 4771300 KB disk space available, that's plenty.
- Amanda Backup Client Hosts Check
- --------------------------------
- Client check: 1 host checked in 0.084 seconds, 0 problems found.
-
-Next make sure that GNU-tar is the dump program currently in use. The easiest
-way to tell if your dumptype is using gnutar is to run the following:
-
- $ amadmin exclude-test disklist CLIENT
-
-Among all the output is the "program" value currently in use. This value is
-also specified with the "program" option in the dumptype. If the dumptype has
-the line "program GNUTAR" your setup should be ready to exclude data.
-If GNU-tar is not in use add the line "program GNUTAR" to the dumptype, and
-then run amcheck again to verify that backups should work. The capitalization
-of GNUTAR is required.
-The dumptype should look something like:
-
- define dumptype exclude-test {
- comment "test dumptype for documentation"
- priority high
- program "GNUTAR"
- }
-
-
- Choosing an exclude mechanism
-
-If the need is to exclude only one file or directory then the easiest way to
-accomplish this is to exclude an individual item explicitly in the dumptype. If
-the need is to exclude multiple files or directories then use an Exclude List.
-
- Exclude Mechanisms
-
-
- Exclude an individual item explicitly in the dumptype
-
-The easiest way to exclude a file or directory is to specify it with the
-"exclude" option in the dumptype. This option accepts an argument of the file
-or directory to be excluded. Amanda allows only one exclude option in any
-dumptype at a time.
-
-Note
-
-UPDATE: Recent Amanda-releases bring the option "exclude append" which enables
-the administrator to define more than one exclusion-pattern within one dumptype
-without using a exclude-list. Please look at the amanda.conf.5-manpage for
-details.
-Any path specified to be excluded must be encapsulated with quotes. Continuing
-with our example from above /var/log/somefile and using the same dumptype as
-above, the dumptype would now look like:
-
- define dumptype exclude-test {
- comment "test dumptype for documentation"
- priority high
- program "GNUTAR"
- exclude "./log/somefile"
- }
-
-Next run amcheck again to verify that there are no problems with the revised
-Amanda configuration. If the data is not being excluded as expected please see
-the Troubleshooting section below. This completes the setup of excluding an
-individual item in the dumptype.
-
- Utilize an Exclude List
-
-An exclude list is a file that resides on the CLIENT machine and contains paths
-to be excluded, one per line. This file can be in any location on the CLIENT so
-long as the same path is specified in the dumptype. Some find /usr/local/etc/
-amanda an appropriate location, but it is up to you. I personally like to have
-a subdirectory for exclude files but it is up to you where you place this file.
-The exclude file may also be placed in the area being archived. This is an easy
-way to have a different exclusion file for each disklist entry without needing
-separate dumptype definitions. To use this technique, enter a path relative to
-the area being archived as the exclude file below instead of an absolute path.
-Connect to CLIENT and create the exclude directory as root. For example:
-
- $ mkdir -p /usr/local/etc/amanda/exclude
- $ cd /usr/local/etc/amanda/exclude
-
-Next create the exclude list for Amanda to use. You can name the exclude file
-anything you wish it to be. Create a file, and in this file place all paths to
-files and directories that are to be excluded. Keeping with the /var example,
-assume that /var/log/XFree86.0.log, and /var/log/maillog need to be excluded.
-Remember that all paths are relative. The exclude list would look like:
-
- ./log/XFree86.0.log
- ./log/maillog
-
-Make sure that permissions are restricted on this file. Run the following as
-root, where exclude-filename is the name of the file you just created. For
-example:
-
- $ chmod 644 /usr/local/etc/amanda/exclude/exclude-filename
-
-This concludes the necessary configuration on the client.
-Connect to SERVER and cd to the exclude-test Amanda configuration directory.
-Edit the Amanda configuration file e.g. amanda.conf. Add an entry similar to
-the following line, to the dumptype for the client in question, where the
-exclude-filename is the file that was created on CLIENT in the step above
-including the quotes. For example:
-
- exclude list "/usr/local/etc/amanda/exclude/exclude-filename"
-
-The new dumptype should look something like:
-
- define dumptype exclude-test{
- comment "test dumptype for documentation"
- priority high
- program "GNUTAR"
- exclude list "/usr/local/etc/amanda/exclude/exclude-filename"
- }
-
-Save the file. Run amcheck again to verify that there are no problems with the
-revised Amanda configuration. If amcheck succeeds then run amdump to verify the
-data is being excluded correctly. If the data is not being excluded as expected
-please see the Troubleshooting section below. This completes the setup of an
-exclude list.
-
- Do not include the data in the disklist
-
-Amanda uses disklist entries to define which directories or partitions should
-be archived. This allows us to exclude data by just not placing the data in
-question in the disklist. Assume that there is a disk mounted on /example. The
-directory /example has five subdirectories "a", "b", "c", "d", and "e". The
-directories "a", "b", and "c" need to be archived, while "d" and "e" should
-not. This can be accomplished by not specifying "d" and "e" in the disklist.
-Using the same dumptype and host in the above examples the disklist would
-contain:
-
- CLIENT /examples/a exclude-test
- CLIENT /examples/b exclude-test
- CLIENT /examples/c exclude-test
-
-Run amcheck to verify that Amanda is working correctly. If the data is not
-being excluded as expected please see the Troubleshooting section below. This
-completes the setup of using a disklist to exclude data.
-
- Expression
-
-Quiz: what is the difference between the following entries in an exclude list?
-
- ./foo
- ./foo/
- ./foo/*
-
-case 1 : directory ./foo won't be in the backup image (that's what you want)
-case 2 : matches nothing (don't use it) case 3 : directory ./foo will be in the
-backup image but nothing below it.
-
- Wildcard Expansion
-
-Amanda has the ability to use wildcard expansion while excluding data as
-implemented by tar(1). The only places that wildcard expansion is allowed is in
-the "exclude" option in the dumptype, or in the exclude list. Some simple
-examples:
-Exclude any file or directory that ends in ".log" e.g. ppp.log, XFree86.0.log
-
- ./*.log
-
-Exclude any file or directory with the string "log" e.g. logfile, maillog,
-syslog, ppp.log, XFree86.0.log
-
- */*log*
-
-Exclude any file or directory that starts with string "cron" and ends in ".gz"
-e.g. cron.1.gz, cron.2.gz, log/cron.1.gz
-
- ./*cron*.gz
-
-The question mark can be used to specify a single character. e.g. log.1, log.2,
-etc
-
- ./log.?
-
-
- Troubleshooting
-
-If you find that you are having trouble getting the exclude patterns to match
-correctly, check out this really cool script written by John R. Jackson.
-ftp://gandalf.cc.purdue.edu/pub/amanda/gtartest-exclude
-This script allows you to test your patterns before placing them in an exclude
-list or in the dumptype. Instructions on how to run the script are included in
-the script.
-
- Broken gnutar?
-
-There are versions of GNU-tar that do not correctly exclude data. Version 1.12
-(plus the Amanda patches from http://www.amanda.org) are known to work
-correctly, as does version 1.13.19 (and later). Anything else is questionable.
-
-Note
-
-UPDATE:Using GNU-tar 1.13.25 is recommended.
-
- The ps command is your friend.
-
-Connect to CLIENT and run a
-
- ps ax | grep tar
-
-(or
-
- ps ef | grep tar
-
-on Solaris)
-to see exactly how the tar command is running. Look in the output for the --
-exclude or --exclude-from options in the running tar process. For example:
-
- $ ps ax | grep tar
-
- ? R 0:37 /bin/tar --create --directory /var
- --listed-incremental /var/lib/amanda/gnutar-lists/CLIENTvar_0.new
- --sparse --one-file-system --ignore-failed-read --totals --file
- /dev/null --exclude-from=/usr/local/etc/amanda/exclude-test/exclude.var
- .
-
-In the above output notice the string "--exclude-from=". The string following
-the "=" is the exclude file currently in use. If the string was "--exclude"
-then the string following the "=" is the file or directory that is currently
-set to be excluded.
-Contact the amanda-users mailing list: mailto://amanda-users@amanda.org.
-Subscription information is available at http://www.amanda.org.
-
-Note
-
-Refer to http://www.amanda.org/docs/exclude.html for the current version of
-this document.
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