Table of Contentsamanda - Advanced Maryland Automatic Network Disk Archiver amdump config amflush [ -f ] config
amcleanup config
amrestore [ options ] tapedevice [ hostname [ diskname ]]
amlabel config label
amcheck [ -m ] [ -w ] config
amadmin config command [ command options ]
amtape config command [ command options ]
Amanda is the "Advanced Maryland Automatic Network Disk Archiver". This manual page gives an overview of the Amanda commands and configuration files for quick reference.
Here are all the Amanda commands. Each one has its own manual page; see those for all the gritty details.
- amdump
- takes care of the nightly automatic Amanda backups. It is normally executed by cron on a computer called the master host. Amdump backs up all of the disks specified in the disklist file (discussed below) to tape or, if there is a problem, to a disk called the holding disk. Once all of the night's backups are performed, amdump sends mail to the operators reporting on the night's failures and successes.
- amflush
- flushes backups from the holding disk to tape. Amflush is only used after amdump has reported that it could not write the backups to tape for some reason. When this happens the backups go to the holding disk instead. One of the operators must then correct the problem with the tape and run amflush.
- amcleanup
- cleans up after an interrupted amdump. This command is only needed if amdump was unable to complete for some reason, usually because the master host crashed in the middle of the backups.
- amrestore
- reads backup files off of Amanda tapes, searching the tape for the right backups. Amrestore is suitable both for interactive restores of single files, and the full restore of all partitions on a blown disk.
- amlabel
- writes special Amanda labels onto tapes. Amdump will not write to an unlabeled tape, or to a labeled tape that should not be overwritten (see TAPE MANAGEMENT below).
- amcheck
- verifies that the correct tape is in the Amanda tape drive. Can optionally be run through crontab such that operators will get mail warning that the night's backups will fail unless corrective action is taken.
- amadmin
- takes care of various administrative tasks, like finding out which tapes are needed to restore a filesystem, forcing computers to do full backups, and looking at schedule balance information.
- amtape
- takes care of various tape changer control operations, like loading particular tapes from the tape rack into the drive, ejecting tapes, and scanning the tape rack.
There are three user-editable files that control the behaviour of Amanda. The first is amanda.conf, the main config file. This file contains a number of parameters that you can use to customize Amanda for your site. Second is the disklist file, which specifies the hosts and disk partitions to back up. Third is the tapelist file, which lists the labeled tapes that are currently in active rotation. These files are described in more detail in the following sections.
All the files are stored in a config directory under /etc/amanda. Often a single site will have more than one configuration; these configurations are named by the directories that their config files are in. For example, a site might have a normal configuration for every-day backups, and a archive configuration for 6-month full archival backups. The config files for these two would be stored under /etc/amanda/normal and /etc/amanda/archive, respectively.
All log and database files generated by Amanda go in corresponding directories under /usr/adm/amanda. In our example, the logs would go in /usr/adm/amanda/normal and /usr/adm/amanda/archive.
There are a number of configuration parameters that control the behavior of the Amanda programs. All of them have default values, so you need not specify the parameter in your amanda.conf if you like the default.
- org
- Default: YOUR ORG. A descriptive name for your configuration. This string is used for the mail report. It should be different for each different Amanda configuration you have.
- mailto
- Default: operators. The list of recipients for the nightly mail report.
- mincycle
- Default: 10. The number of days in the backup cycle. Each disk will get a full backup in this many days.
- maxcycle
- Default: 12. Amanda dynamically adjusts the backup schedule, moving full dumps of disks forward to keep the dump schedule in balance, and delaying full dumps if the tape would otherwise overflow. Amanda will not delay a full dump of a disk if that would cause it to go more than maxcycle days between full dumps.
- tapecycle
- Default: 15. The number of tapes in your active tape cycle. This number must be at least one larger than your mincycle parameter. In practice you should have 5 or more slack days in the tape schedule to allow time for schedule adjustments or disaster recovery.
- dumpuser
- Default: bin. The login name that Amanda uses to run the backups. The slave hosts must let the master host in as this user.
- diskdir
- Default: /dumps/amanda. The path name of the holding disk. Backups are deposited under this directory when no tape is available.
- disksize
- Default: 200. The size of the holding disk available to Amanda, in megabytes.
- tapedev
- Default: /dev/rmt8. The path name of the tape device file.
- labelstr
- Default: .*. The tape label constraint regular expression. All tape labels generated and used by this configuration must match the regular expression. If multiple configurations are run from the same master host, it is helpful to constrain their labels to different strings (for example, "DAILY[0-9]*" vs. "ARCHIVE[0-9]*") to avoid overwriting each other's tapes.
- tapetype
- Default: EXABYTE. The type of tape drive in tapedev. This refers to one of the defined tapetypes in the config file, which specify various tape parameters, like the length, filemark size, and speed of the tape device.
- netusage
- Default: 300. The maximum network bandwidth allocated to Amanda, in Kbytes per second.
- inparallel
- Default: 10. The maximum number of backups that Amanda will attempt to run in parallel. Amanda will stay within the constraints of network bandwidth and holding disk space available, so it doesn't hurt to set this number a bit high. Some contention can occur with larger numbers of dumps, but this effect is relatively small on most systems.
- bumpsize
- Default: 10 MB. The minimum savings required to trigger an automatic bump from incremental level one to level two. If Amanda determines that a level two dump will be this much less than a level one, it will do a level two.
- bumpmult
- Default: 2. The bump multiplier. Amanda multiplies the bumpsize by this factor for each level. This prevents active filesystems from bumping too much by making it harder to bump to the next level. For example, with the default bumpsize and bumpmult, the bump threshold will be 10 MB for level one, 20 MB for level two, 40 MB for level three, and so on.
- bumpdays
- Default: 2. To insure redundancy in the dumps, Amanda will keep filesystems at the same incremental level for at least bumpdays days, even if the bump threshold criteria are met.
- diskfile
- Default: disklist. The file name for the disklist file.
- infofile
- Default: /usr/adm/amanda/curinfo. The file name for the historical information database file.
- logfile
- Default: /usr/adm/amanda/log The file name for the nightly log file.
- tapefile
- Default: tapelist. The file name for the active tape list file.
The disklist file determines which disks will be backed up by Amanda. Disks are initially added to the file by the operators. The disklist file contains a one-line entry per disk, of the form: hostname diskdevice dumptype
Lines starting with # are ignored, as are blank lines. The fields have the following meanings:
- hostname
- is the local name of the host to be backed up.
- diskdevice
- is the name of the disk device to be backed up, without the /dev/ prefix.
- dumptype
refers to one of the dumptypes defined in the config file. These dumptypes specify various parameters, like whether or not to compress the dumps, whether to record the dump results in /etc/dumpdates, and the disk's relative priority.
The tapelist file contains the list of tapes that are in active rotation. This file is maintained entirely by Amanda and does not need to be created or edited by the operators for normal operation. It contains lines of the form:
YYYYMMDD LABEL
Where YYYYMMDD is the date that the tape was written, and LABEL is the user-supplied label of the tape, as written by the amlabel program. This file is maintained by the Amanda programs and should not be edited by hand.
Amanda will refuse to write to any unlabeled tape, or to a labeled tape that is considered active and should not be overwritten. There need to be more tapes in active rotation than there are days in the backup cycle to prevent the overwriting of a needed backup file when a problem occurs.
James da Silva <jds@cs.umd.edu>
University of Maryland, College Park
amadmin(8), amdump(8), amflush(8), amcleanup(8), amrestore(8), amlabel(8), amcheck(8), dump(8)
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