amanda - Advanced Maryland Automatic Network Disk Archiver

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 them for all the gory details.

amdump

Take care of automatic AMANDA backups. This is normally executed by cron on a computer called the tape server host and requests backups of file systems located on backup clients. Amdump backs up all disks in the disklist file (discussed below) to tape or, if there is a problem, to a special holding disk. After all backups are done, amdump sends mail reporting failures and successes.

amflush

Flush backups from the holding disk to tape. Amflush is used after amdump has reported it could not write backups to tape for some reason. When this happens, backups stay in the holding disk. Run amflush after the tape problem is corrected to write backups from the holding disk to tape.

amcleanup

Clean up after an interrupted amdump. This command is only needed if amdump was unable to complete for some reason, usually because the tape server host crashed while amdump was running.

amrecover

Provides an interactive interface to browse the AMANDA index files (backup image catalogues) and select which tapes to recover files from. It can also run amrestore and a restore program (e.g. tar) to actually recover the files.

amrestore

Read an AMANDA tape, searching for requested backups. Amrestore is suitable for everything from interactive restores of single files to a full restore of all partitions on a failed disk.

amlabel

Write an AMANDA format label onto a tape. All AMANDA tapes must be labeled with amlabel. Amdump and amflush will not write to an unlabeled tape (see TAPE MANAGEMENT below).

amcheck

Verify the correct tape is mounted and all file systems on all backup client systems are ready to be backed up. Often run by cron before amdump to generate a mail warning that backups might fail unless corrective action is taken.

amadmin

Take care of administrative tasks like finding out which tapes are needed to restore a filesystem, forcing hosts to do full backups of selected disks and looking at schedule balance information.

amtape

Take care of tape changer control operations like loading particular tapes, ejecting tapes and scanning the tape storage slots.

amverify

Check AMANDA backup tapes for errors.

amrmtape

Delete a tape from the AMANDA databases.

amstatus

Report the status of a running or completed amdump.

amoverview

Display a chart of hosts and file systems backed up every run.

amplot

Generate utilization plots of AMANDA runs for performance tuning.

amreport

Generate an AMANDA summary E-mail report.

amtoc

Generate table of content files for AMANDA tapes.

amcheckdb

Verify every tape AMANDA knows about is consistent in the database.

amgetconf

Look up parameters in the AMANDA configuration file.

amtapetype

Generate a tapetype definition.

There are three user-editable files that control the behavior of AMANDA.

The first is amanda.conf, the main configuration file. It contains parameters to customize AMANDA for the site. Refer to the amanda.conf(5), manpage for details on AMANDA configuration parameters.

Second is the disklist file, which lists hosts and disk partitions to back up.

Third is the tapelist file, which lists tapes that are currently active. These files are described in more detail in the following sections.

All files are stored in individual configuration directories under /usr/local/etc/amanda/. A site will often have more than one configuration. For example, it might have a normal configuration for everyday backups and an archive configuration for infrequent full archival backups. The configuration files would be stored under directories /usr/local/etc/amanda/normal/ and /usr/local/etc/amanda/archive/, respectively. Part of the job of an AMANDA administrator is to create, populate and maintain these directories.

All log and database files generated by AMANDA go in corresponding directories somewhere. The exact location is controlled by entries in amanda.conf. A typical location would be under /var/adm/amanda. For the above example, the files might go in /var/adm/amanda/normal/ and /var/adm/amanda/archive/.

As log files are no longer needed (no longer contain relevant information), AMANDA cycles them out in various ways, depending on the type of file.

Detailed information about amdump runs are stored in files named amdump.NN where NN is a sequence number, with 1 being the most recent file. Amdump rotates these files each run, keeping roughly the last tapecycle (see below) worth of them.

The file used by amreport to generate the mail summary is named log.YYYYMMDD.NN where YYYYMMDD is the datestamp of the start of the amdump run and NN is a sequence number started at 0. At the end of each amdump run, log files for runs whose tapes have been reused are renamed into a subdirectory of the main log directory (see the logdir parameter below) named oldlog. It is up to the AMANDA administrator to remove them from this directory when desired.

Index (backup image catalogue) files older than the full dump matching the oldest backup image for a given client and disk are removed by amdump at the end of each run.

The disklist file determines which disks will be backed up by AMANDA. The file usually contains one line per disk:

hostname diskname [diskdevice] dumptype [spindle [interface] ]

All pairs [ hostname diskname ] must be unique.

Lines starting with # are ignored, as are blank lines. The fields have the following meanings:

hostname

The name of the host to be backed up. If diskdevice refers to a PC share, this is the host AMANDA will run the Samba smbclient program on to back up the share.

diskname

The name of the disk (a label). In most case, you set your diskname to the diskdevice and you don't set the diskdevice. If you want multiple entries with the same diskdevice, you must set a different diskname for each entry. It's the diskname that you use on the commandline for any AMANDA command. Look at the example/disklist file for example.

diskdevice

Default: same as diskname. The name of the disk device to be backed up. It may be a full device name, a device name without the /dev/ prefix, e.g. sd0a, or a mount point such as /usr.

It may also refer to a PC share by starting the name with two (forward) slashes, e.g. //some-pc/home. In this case, the program option in the associated dumptype must be entered as GNUTAR. It is the combination of the double slash disk name and program GNUTAR in the dumptype that triggers the use of Samba.

dumptype

Refers to a dumptype defined in the amanda.conf file. Dumptypes specify backup related parameters, such as whether to compress the backups, whether to record backup results in /etc/dumpdates, the disk's relative priority, etc.

spindle

Default: -1. A number used to balance backup load on a host. AMANDA will not run multiple backups at the same time on the same spindle, unless the spindle number is -1, which means there is no spindle restriction.

interface

Default: local. The name of a network interface definition in the amanda.conf file, used to balance network load.

Instead of naming a dumptype, it is possible to define one in-line, enclosing dumptype options within curly braces, one per line, just like a dumptype definition in amanda.conf. Since pre-existing dumptypes are valid option names, this syntax may be used to customize dumptypes for particular disks.

A line break must follow the left curly bracket.

For instance, if a dumptype named normal is used for most disks, but use of the holding disk needs to be disabled for the file system that holds it, this would work instead of defining a new dumptype:

hostname diskname [ diskdevice ] { normal holdingdisk no } [ spindle [ interface ] ]

The tapelist file contains the list of tapes in active use. This file is maintained entirely by AMANDA and should not be created or edited during normal operation. It contains lines of the form:

YYYYMMDD label flags

Where YYYYMMDD is the date the tape was written, label is a label for the tape as written by amlabel and flags tell AMANDA whether the tape may be reused, etc (see the reuse options of amadmin).

Amdump and amflush will refuse to write to an unlabeled tape, or to a labeled tape that is considered active. There must be more tapes in active rotation (see the tapecycle option) than there are runs in the backup cycle (see the dumpcycle option) to prevent overwriting a backup image that would be needed to do a full recovery.

The normal value for the tapedev parameter, or for what a tape changer returns, is a full path name to a non-rewinding tape device, such as /dev/nst0 or /dev/rmt/0mn or /dev/nst0.1 or whatever conventions the operating system uses. AMANDA provides additional application level drivers that support non-traditional tape-simulations or features. To access a specific output driver, set tapedev (or configure your changer to return) a string of the form driver:driver-info where driver is one of the supported drivers and driver-info is optional additional information needed by the driver.

The supported drivers are:

tape

This is the default driver. The driver-info is the tape device name. Entering

tapedev /dev/rmt/0mn

is really a short hand for

tapedev tape:/dev/rmt/0mn

.

null

This driver throws away anything written to it and returns EOF for any reads except a special case is made for reading a label, in which case a "fake" value is returned that AMANDA checks for and allows through regardless of what you have set in labelstr. The driver-info field is not used and may be left blank:

tapedev null:

The length value from the associated tapetype is used to limit the amount of data written. When the limit is reached, the driver will simulate end of tape.

This driver should only be used for debugging and testing, and probably only with the record option set to no.

rait

Redundant Array of Inexpensive (?) Tapes. Reads and writes tapes mounted on multiple drives by spreading the data across N-1 drives and using the last drive for a checksum. See docs/RAIT for more information.

The driver-info field describes the devices to use. Curly braces indicate multiple replacements in the string. For instance:

tapedev rait:/dev/rmt/tps0d{4,5,6}n

would use the following devices:

/dev/rmt/tps0d4n /dev/rmt/tps0d5n /dev/rmt/tps0d6n

file

This driver emulates a tape device with a set of files in a directory. The driver-info field must be the name of an existing directory. The driver will test for a subdirectory of that named data and return offline until it is present. When present, the driver uses two files in the data subdirectory for each tape file. One contains the actual data. The other contains record length information.

The driver uses a file named status in the file device directory to hold driver status information, such as tape position. If not present, the driver will create it as though the device is rewound.

The length value from the associated tapetype is used to limit the amount of data written. When the limit is reached, the driver will simulate end of tape.

One way to use this driver with a real device such as a CD-writer is to create a directory for the file device and one or more other directories for the actual data. Create a symlink named data in the file directory to one of the data directories. Set the tapetype length to whatever the medium will hold.

When AMANDA fills the file device, remove the symlink and (optionally) create a new symlink to another data area. Use a CD writer software package to burn the image from the first data area.

To read the CD, mount it and create the data symlink in the file device directory.

AMANDA processes on the tape server host run as the dumpuser user listed in amanda.conf. When they connect to a backup client, they do so with an AMANDA-specific protocol. They do not, for instance, use rsh or ssh directly.

On the client side, the amandad daemon validates the connection using one of several methods, depending on how it was compiled and on options it is passed:

.rhosts

Even though AMANDA does not use rsh, it can use .rhosts-style authentication and a .rhosts file.

.amandahosts

This is essentially the same as .rhosts authentication except a different file, with almost the same format, is used. This is the default mechanism built into AMANDA.

The format of the .amandahosts file is:

hostname [ username ]

If username is ommitted, it defaults to the user running amandad, i.e. the user listed in the inetd or xinetd configuration file.

Kerberos

AMANDA may use the Kerberos authentication system. Further information is in the docs/KERBEROS file that comes with an AMANDA distribution.

For Samba access, AMANDA needs a file on the Samba server (which may or may not also be the tape server) named /etc/amandapass with share names, (clear text) passwords and (optional) domain names, in that order, one per line, whitespace separated. By default, the user used to connect to the PC is the same for all PC's and is compiled into AMANDA. It may be changed on a host by host basis by listing it first in the password field followed by a percent sign and then the password. For instance:

//some-pc/home normalpw //another-pc/disk otheruser%otherpw.fi With clear text passwords, this file should obviously be tightly protected. It only needs to be readable by the AMANDA-user on the Samba server.

You can find further information in the docs/SAMBA file that comes with an AMANDA distribution.

All host and disk arguments to programs are special expressions. The command applies to all disks that match your arguments. This section describes the matcher.

The matcher matches by word, each word is a glob expression, words are separated by the separator '.' for host and '/' for disk. You can anchor the expression at left with a '^'. You can anchor the expression at right with a '$'. The matcher is case insensitive for host but is case sensitive for disk. A match succeeds if all words in your expression match contiguous words in the host or disk. . word separator for a host/ word separator for a disk^ anchor at left$ anchor at right? match exactly one character except the separator* match zero or more characters except the separator**match zero or more characters including the separator

A datestamp expression is a range expression where we only match the prefix. Leading ^ is removed. Trailing $ forces an exact match. 20001212-14match all dates beginning with 20001212, 20001213 or 2000121420001212-4same as previous20001212-24match all dates between 20001212 and 200012242000121match all dates that start with 2000121 (20001210-20001219)2match all dates that start with 2 (20000101-29991231)2000-10match all dates between 20000101-20101231200010$match only 200010

James da Silva, <jds@amanda.org> : Original text

Stefan G. Weichinger, <sgw@amanda.org>, maintainer of the AMANDA-documentation: XML-conversion, major update

amadmin(8), amanda.conf(5), amcheck(8), amcheckdb(8), amcleanup(8), amdd(8), amdump(8), amflush(8), amgetconf(8), amlabel(8), ammt(8), amoverview(8), amplot(8), amrecover(8), amreport(8), amrestore(8), amrmtape(8), amstatus(8), amtape(8), amtapetype(8), amtoc(8), amverify(8), amverifyrun(8)