Interacting with Tape Library on CentOS 7 via mtx
Figured it out!
mtx
functions only on "generic" SCSI devices. The /dev/sch0
device provided by the ch
kernel driver is something of a red herring.
It turns out that SCSI devices are given "generic" device files, in addition to whatever driver-backed specific devices are created. You can find those using lsscsi
:
$ lsscsi --generic
[0:0:19:0] enclosu CISCO UCS 240 0809 - /dev/sg0
[0:2:0:0] disk LSI MR9271-8i 3.24 /dev/sda /dev/sg1
[1:0:0:0] tape IBM ULTRIUM-HH6 E4J1 /dev/st0 /dev/sg2
[1:0:0:1] mediumx QUANTUM UHDL 0091 /dev/sch0 /dev/sg3
These were actually alluded to in the dmesg
output above. Using the generic device, mtx
works fine with the SuperLoader 3 on CentOS 7:
$ sudo mtx -f /dev/sg3 status
Storage Changer /dev/sg3:1 Drives, 16 Slots ( 0 Import/Export )
Data Transfer Element 0:Empty
Storage Element 1:Empty
Storage Element 2:Empty
Storage Element 3:Empty
Storage Element 4:Empty
Storage Element 5:Empty
Storage Element 6:Empty
Storage Element 7:Empty
Storage Element 8:Empty
Storage Element 9:Empty
Storage Element 10:Empty
Storage Element 11:Empty
Storage Element 12:Empty
Storage Element 13:Empty
Storage Element 14:Empty
Storage Element 15:Empty
Storage Element 16:Empty
All that's left to do is to symlink /dev/changer
to /dev/sg3
for convenience.