Autochanger resource

Configuration directives for the Autochanger resource. Every directive is listed; value types and defaults are noted where the source provides them.

Changer Command

Changer Command = <name-string>

The <name-string> specifies an external program to be called that will automatically change volumes as required by NGBackup. Most frequently, you will specify the NGBackup supplied mtx-changer script as follows. If it is specified here, it need not be specified in the Device resource. If it is also specified in the Device resource, it will take precedence over the one specified in the Autochanger resource.

Changer Device

Changer Device = <name-string>

The specified <name-string> gives the system file name of the autochanger device name. If specified in this resource, the Changer Device name is not needed in the Device resource. If it is specified in the Device resource (see above), it will take precedence over one specified in the Autochanger resource.

Device

Device = <Device-name1, device-name2, ...>

Specifies the names of the Device resource or resources that correspond to the autochanger drive. If you have a multiple drive autochanger, you must specify multiple Device names, each one referring to a separate Device resource that contains a Drive Index specification that corresponds to the drive number base zero. You may specify multiple device names on a single line separated by commas, and/or you may specify multiple Device directives. This directive is required.

list

returns one line for each cassette in the autochanger in the format <slot>:<barcode>. Where the <slot> is the non-zero integer representing the slot number, and <barcode> is the barcode associated with the cassette if it exists and if you autoloader supports barcodes. Otherwise the barcode field is blank.

load

loads a specified slot (note, some autochangers require a 30 second pause after this command) into the drive.

loaded

returns number of the slot that is loaded, base 1, in the drive or 0 if the drive is empty.

Name

Name = <Autochanger-Name>

Specifies the Name of the Autochanger. This name is used in the Director’s Storage definition to refer to the autochanger. This directive is required.

slots

returns total number of slots in the autochanger.

unload

unloads the device (returns cassette to its slot).

Native mtx-changer engine

NGBackup ships a native Rust changer engine (backup-sd-changer) that drives the SCSI medium-changer through mtx/mt directly — no external mtx-changer shell script. Set NativeChanger = yes and the SD parses mtx status itself and issues mtx load/unload/transfer and mt offline/status; leave it unset (the default) to keep shelling out to the ChangerCommand script.

The directives below mirror the stock mtx-changer.conf knobs and only apply when NativeChanger = yes.

NativeChanger

NativeChanger = <yes|no> (default no)

When yes, the SD drives the changer with its built-in engine instead of the external ChangerCommand script.

Mtx

Mtx = <path> (default /usr/sbin/mtx)

Path to the mtx binary used for load / unload / transfer / status.

Mt

Mt = <path> (default mt)

Path to the mt binary used for drive offline / ready probes.

TapeInfo

TapeInfo = <path>

Path to the tapeinfo binary (optional; used for TapeAlert queries).

Offline

Offline = <yes|no> (default no)

Issue mt offline on the drive before an unload (some libraries require it).

OfflineSleep

OfflineSleep = <time> (default 0)

Wait this long after an offline before continuing.

LoadSleep

LoadSleep = <time> (default 0)

Wait this long after a successful load before returning (some autochangers need a settle pause).

Inventory

Inventory = <yes|no> (default no)

Run mtx inventory before a status / list so the library re-reads barcodes.

VxaPacketLoader

VxaPacketLoader = <yes|no> (default no)

Parse the variant Storage-Element line that some VXA PacketLoaders emit.

Example

Autochanger {
  Name = mhvtl-lib10
  ChangerDevice = /dev/sg3          # the medium changer (lsscsi -g)
  NativeChanger = yes               # use the built-in engine
  Mtx = /usr/bin/mtx
  Offline = no
  LoadSleep = 0
  Device = drive-0, drive-1, drive-2, drive-3
}

See the Storage daemon operations section of the Command-line tools reference for the transfer and mount/unmount console verbs that drive the changer.