Provided by: amanda-common_2.6.1p1-2_i386 bug


       amanda-changers - Configuring and Using Amanda Changers


       Amanda uses changers to arbitrate access to devices (amanda-devices(7))
       and data volumes. Changers provide an abstraction of tape robots, but
       are used to manage non-tape media, too. Amanda communicates with
       changers through the Changer API. This manpage contains a user-level
       overview of the API, and does not address details that are only of
       concern to developers. For that purpose, consult the Amanda source code


       The Amanda Changer API is in transition from version 1.0 - driven by
       shell scripts invoked for each changer operation - to version 2.0,
       composed of perl objects that can manage parallel access to multiple
       devices and other complexity. When this transition is complete, Amanda
       devices will, in general, be specified via a changer, which will
       provide the necessary device specifier to access a requested volume. In
       the interim, support for the "new" changer syntax is limited to the
       experimental amvault(8).


       Changer specifications are strings like chg-disk:/my/vtapes. The chg-
       prefix serves to differentiate changers from devices (see amanda-
       devices(7)). The next portion (disk, in this case) identifies the
       particular changer driver to use, and everything that follows the : is
       interpreted by the driver.

       A name which does not match this pattern, but which matches an old
       changer script (e.g., chg-zd-mtx), invokes the backward-compatibility
       changer driver as chg-compat:chg-zd-mtx. If the name does not match an
       old changer, then it is treated as an Amanda device, and is wrapped by
       the single-device changer, e.g., chg-single:tape:/dev/rmt/0.

       Changers which require additional parameters can also be described in
       amanda.conf(5) with "changer" sections, for example,

       define changer hp-robot {
           tapedev "chg-robot:/dev/sg1"
           property "drives" "0=/dev/nst0;1=/dev/nst0"
           property "slots" "1-10"
       (note that "chg-robot" is not yet implemented, so this is
       hypothetical). A changer defininition creates a changer "alias", in
       this case named hp-robot, which can then be named where an application
       expects a changer - for example, the target of the amvault command.


       This section lists the changer drivers included with Amanda, and basic
       instructions for using them. For complete How-To information, consult
       the Amanda wiki at

   chg-disk (new)
       tpchanger "chg-disk:/u01/vtapes"

       This changer driver replaces the old chg-disk, supporting parallel
       access to vtapes stored in directories named slotN in the directory
       specified after chg-disk:. It does so by creating numbered "drives" so
       that simultaneous processes can access distinct slots.

   chg-disk (old)
       tapedev "file:/u01/vtapes"
       tpchanger "chg-disk"

       This changer script supports sequential access to vtapes stored in
       directories named slotN in the directory specified by the tapedev

       tpchanger "chg-multi"
       changerfile "chg-multi-state"

       This script simply round-robins a number of distinct device names, as
       specified in its configuration file. It is useful when all volumes for
       a configuration have different device names -- for example, with S3
       devices. The changerfile need not exist; it is used as a prefix for
       filenames of state files.

       tpchanger "chg-manual"
       changerfile "chg-manual.conf"

       This script simply provides distinct device names in a round-robin
       fashion, as specified in its configuration file. It is useful when all
       volumes for a configuration have different device names -- for example,
       with S3 devices. The configuration file parameters are (as listed in
       the script):

       resend_mail=900       # resend mail every __ seconds
       timeout_mail=604800   # time out after this many seconds (default 7 days)
       request="[type]"      # How to request a new tape (default "tty_email")
         request="tty"       # Use the tty to ask the user to change tape.
                             # Can´t be use by cron
         request="email"     # Send an email to ask the user to change tape.
         request="tty_email" # Use the tty if it exist or send an email.

       tpchanger "chg-zd-mtx"
       changerdev "/dev/sg0"         # used with ´mtx -f´
       changerfile "chg-zd-mtx.conf"
       tapedev "tape:/dev/nst0"

       This script interfaces with a tape drive using the Zubkoff/Dandelion
       version of mtx. That´s the version that takes a device specifier with
       the -f option and has subcommands like status. The configuration file
       parameters are (as listed in the script itself):

       firstslot=?                 #### First storage slot (element)
       lastslot=?                  #### Last storage slot (element)
       cleanslot=-1                #### Slot with cleaner tape -- default is "-1"
                                   #### Set negative to indicate no cleaner available
       driveslot=0                 #### Drive slot number.  Defaults to 0
                                   #### Use the ´Data Transfer Element´ you want
       autoclean=0                 #### Set to ´1´ or greater to enable
       autocleancount=99           #### Number of access before a clean.
       havereader=0                #### If you have a barcode reader, set to 1.
       offline_before_unload=0     #### Does your robot require an
                                   #### ´mt offline´ before mtx unload?
       poll_drive_ready=NN         #### Time (seconds) between tests to see if
                                   #### the tape drive has gone ready (default: 3).
       max_drive_wait=NN           #### Maximum time (seconds) to wait for the
                                   #### tape drive to become ready (default: 120).
       initial_poll_delay=NN       #### initial delay after load before polling for
                                   #### readiness
       slotinfofile=FILENAME       #### record slot information to this file, in
                                   #### the line-based format "SLOT LABEL\n"

       tpchanger "chg-rait"
       changerfile "chg-rait.conf"

       This changer script constructs RAIT devices out of the devices provided
       by several "sub-changers". The configuration file specifies nchangers,
       the number of subchangers, and then provides tpchanger, changerdev_N,
       changerfile_N, and tpchanger_N for each sub-changer, 1 through N.

       tpchanger "chg-null"

       This changer always provides the device "null:". It is sometimes useful
       in conjunction with chg-rait.

   Unmaintained Changers
       Amanda has many other changer scripts and programs beyond those
       described here (see the changer-src/ in the source directory), but most
       of these scripts are unmaintained and undocumented, and will be removed
       when the new changer API is fully implemented.


       amanda(8), amanda.conf(5), amanda-devices(7),


       Dustin J. Mitchell <>
           Zmanda, Inc. (