User Commands

NAME¶

vtllibrary - user space daemon to handle SCSI SMC commands for Virtual Tape Library.

SYNOPSIS¶

vtllibrary -h -- print a help message and exit, or
vtllibrary [OPTIONS] -q QUEUE_ID -- Emulate a tape library for queue QUEUE_ID.

DESCRIPTION¶

This command emulates a tape library device, using queue QUEUE_ID, which represent the message queue number used for this daemon. This number is derived from the device.conf where it must be unique. Media files can be created using OPTIONS are from:

-d: Enable debug logging (to stdout). Do not background the process, and set verbosity to level 9.
-v[N]: Enable verbose logging (to syslog) at level N (default 1).
-F: Run in the foreground, not as a daemon.
-fFIFO: Near real time device state information will be available for external utilities by reading from this fifo. This switch has a higher precedence than the 'fifo:' entry in device.conf.

The vtllibrary daemon simulates a tape library device, and is started by systemd(1), as needed, one invocation per Tape Library being simulated. The vtllibrary daemon registers each vtltape(1) via message queue. The vtllibrary reads /etc/mhvtl/library_contents.* and dynamically builds an internal structure of Storage slots and Media Access slots. All media movement is performed on internal structures only. The configuration file is never changed, i.e. a re-start of the daemon will result in the loss of any previous media movements.

When media is moved to/from a "Data transfer element" (tape drive), a (un)load message is sent via the drive 'slot number' message Q number to load/unload the barcode.

FILES¶

/etc/mhvtl/device.conf -- to find which library_contents.* files to examine
/etc/mhvtl/library_contents.*

AUTHOR¶

Written by Mark Harvey

BUGS¶

Does not implement the complete SCSI SMC-2/SMC-3 command set.

REPORTING BUGS¶

Report bugs to <markh794@gmail.com> <mark.harvey@nutanix.com>.