The \fBvchanger(8)\fR utility is used to emulate and control a virtual autochanger within the Bacula network backup system environment\&. Backup volumes stored on multiple disk filesystems are mapped to a single set of virtual slots\&. This allows an unlimited number of virtual drives and an unlimited number of virtual slots spread across an unlimited number of physical disk drives to be assigned to a single autochanger\&. This allows unlimited scaling of the cirtual autochanger simply by adding additional disk drives\&.
Vchanger is primarily deigned for use with removable disk drives\&. Its ability to interact with Bacula and determine removable drive mount points through udev allow for plug\-n\-play operation when attaching and detaching removable disk drives\&.
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The first argument, \fIconfig\fR, is required amd specifies the path to the \fBvchanger\&.conf(5)\fR configuration file of the autochanger to be commanded\&.
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The second argument, \fIcommand\fR, is the Bacula Autochanger Interface command to perform\&.
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The third argument, \fIslot\fR, is required for the LOAD, LOADED, and UNLOAD commands and gives the slot number of the volume to act upon\&.
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The fourth argument, \fIdevice\fR, is required for the LOAD, LOADED, and UNLOAD commands\&. It normally specifies the device node of a tape drive for tape autochangers\&. For vcahnger, it is only required as a place holder, and its value is ignored\&.
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The fifth argument, \fIdrive\fR, is required for the LOAD, LOADED, and UNLOAD commands and gives the zero\-based drive number to act upon\&.
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Vchanger implements the commands defined by the Bacula Autochanger Interface specification\&. The following commands are supported\&.
.PP
\fBLIST\fR
.RS4
List slots, one line each, in the format slot:label\&.
.RE
.PP
\fBLOAD\fR\fIslot\fR\fIdevice\fR\fIdrive\fR
.RS4
Load the volume in slot
\fIslot\fR
into drive
\fIdrive\fR\&.
.RE
.PP
\fBLOADED\fR\fIslot\fR\fIdevice\fR\fIdrive\fR
.RS4
Print the slot number currently loaded into drive
\fIdrive\fR, or print
\fI0\fR
if the drive is unloaded\&.
.RE
.PP
\fBSLOTS\fR
.RS4
Print the number of slots\&.
.RE
.PP
\fBUNLOAD\fR\fIslot\fR\fIdevice\fR\fIdrive\fR
.RS4
Unload the volume currently loaded in drive
\fIdrive\fR\&.
.RE
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Vchanger also implements the following undocumented comands
.PP
\fBLISTALL\fR
.RS4
List drive status followed by slot status, one line for each drive or slot, in the format type:number:status:label, where
\fItype\fR
is D for a drive or S for a slot,
\fInumber\fR
is the drive or slot number,
\fIstatus\fR
is E for empty or F for full, and
\fIlabel\fR
is the volume label (barcode)\&.
.RE
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Additionally, the following extended commands are supported\&.
\fImag_ndx\fR\&. Magazines are directories and/or filesystems that have been defined in the
\fBvchanger(5)\fR
configuration file given by
\fIconfig\fR\&. The magazine index is based on the order in which the Magazine directives appear in the configuration file, where index zero is the first occurrence\&. Optionally,
\fIstart\fR
specifies the minimum integer uniqueness number to append to a prefix string when generating filenames for the created volume files\&. The default is to use a uniqueness number greater than highest number currently used for any volume file on the selected magazine\&.
.RE
.PP
\fBLISTMAGS\fR
.RS4
List the status of all assigned magazines (directories and filesystems), one per line, in the format mag:count:start:mnt, where
\fImag\fR
is zero\-based index of the magazines specified in configuration file
\fIconfig\fR,
\fIcount\fR
is the number of volume files on that magazine,
\fIstart\fR
is the virtual slot number of the beginning of the range of slots mapped to the magazine\(cqs volume files, and
\fImnt\fR
is the magazine\(cqs directory/mountpoint if mounted, or blank if not currently mounted\&.
.RE
.PP
\fBREFRESH\fR
.RS4
Refresh state information for the autochanger defined by the configuration file
By default, vcahgner will invoke bconsole and issue commands to Bacula when certain operator actions are needed\&. When anything happens that changes the current set of volume files being used, (the virtual slot to volume file mapping), vchanger will invoke bconsole and issue an \fIupdate slots\fR command\&. For example, when the operator attaches a removable drive defined as one of the changer\(cqs magazines, the volume files on the removable drive must be mapped to virtual slots\&. Since the slot\-to\-volume mapping will have changed, Bacula will need to be informed of the change via the \fIupdate slots\fR command\&. The \fBREFRESH\fR command can be invoked to force vchanger to update state info and trigger \fIupdate slots\fR if needed\&.
Additionally, when new volumes are created with the \fBCREATEVOLS\fR command, vchanger will invoke bconsole and issue a \fIlabel barcodes\fR command to allow Bacula to write volume labels on the newly created volume files\&.
Override the default user to run as when invoked by root\&. The default is normally specified in the configuration file given by
\fIconfig\fR\&.
.RE
.PP
\fB\-g, \-\-group\fR=\fIgid\fR
.RS4
Override the default group to run as when invoked by root\&. The default is normally specified in the configuration file given by
\fIconfig\fR\&.
.RE
.PP
\fB\-\-pool\fR=\fIpool\fR
.RS4
Overrides the name of the pool into which volumes created by the CREATEVOLS command will be placed when vchanger is configured to label new volumes by sending Bacula a
\fIlabel barcodes\fR
command\&. The default is given by the
\fIDefault Pool\fR
setting in the configuration file\&.
.RE
.PP
\fB\-l, \-\-label\fR=\fIprefix\fR
.RS4
Overrides the default volume label prefix when generating names for new volume files created by the CREATEVOLS command\&. The default is
\fIname_ndx\fR, where
\fIname\fR
is the autochanger name and
\fIndx\fR
is the magazine index\&.
.RE
.PP
\fB\-\-help\fR
.RS4
Displays command help for the vchanger command\&.
.RE
.PP
\fB\-\-version\fR
.RS4
Displays vchanger version information\&.
.RE
.SH"NOTES"
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See the vchangerHowto\&.html file included in the doc directory of the source distribution for more detailed documentation\&.
This is free software; See the source for copying conditions\&. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE\&.
