Why “cfgadm” does not show “med-changer” device of SAS attached tape-library?

Question

Trying to set up a tape library NEOs StorageLoader LTO7 and also old PowerVault 124T I am facing following problem and cannot find any helpful answer.

Using either Openindiana 151a8, Openindiana Hipster 2017.4 or current SmartOS none of them creates device for tape-changer LUN1 (to be used by mtx). Only tape-drive device (LUN0) is shown:

user@server1:~# cfgadm -al
Ap_Id                          Type         Receptacle   Occupant     Condition
...
c3::rmt/1                      tape         connected    configured   unknown
...

Which maps to /dev/rmt/1 and is perfectly usable by mt tool. I have read a lot about using devfsadm -C -v and booting with reconfigure option but nothing solved situation.

How to get /dev/scsi/changer/... for mtx ?

BTW: Tape library is attached to LSI 9207-4i4e HBA controller and OS driver for this is mpt_sas, which seems to see LUN1 according to LSIUtil and boot screen output. /var/adm/messages does not show any useful info execpt a warning, that multipathing will be disabled due to invalid WWN of tape-changer.

Answer 1

Very easy to solve (after hours of wasting time by trying to modify /kernel/drv/sgen.conf and some others as suggested by driver's man pages):

Simply configure system to use sgen driver for SCSI tape-changer LUN by issuing following command:

user@server1:~# update_drv -av -i '"scsiclass,08"' sgen
exit status = 0
devfsadm[1384]: verbose: symlink /dev/scsi/changer/c3t500E09E0001BFE72d1 -> ../../../devices/pci@0,0/pci8086,e04@2/pci1000,3030@0/iport@8/medium-changer@w500e09e0001bfe72,1:changer

et voilà

user@server1:~# cfgadm -al
Ap_Id                          Type         Receptacle   Occupant     Condition
...
c3::rmt/1                      tape         connected    configured   unknown
c3::scsi/changer/c3t5000E1116  med-changer  connected    configured   unknown
...

Proof that device is handled by sgen driver:

user@server1:~# cat /etc/path_to_inst | grep sgen
"/pci@0,0/pci8086,e04@2/pci1000,3030@0/iport@8/medium-changer@w5000e11164a8d002,1" 1 "sgen"

Now mtx is ready to operate the robot:

user@server1:~# mtx -f /dev/scsi/changer/c3t5000E11164A8D002d1 inquiry
Product Type: Medium Changer
Vendor ID: 'BDT     '
Product ID: 'FlexStor II     '
Revision: '5.10'
Attached Changer API: No

If links in /dev tree are messed up you may use devfsadm to clean up:

user@server1:~# devfsadm -C -v

BTW: Tape drive needs probalby needs st SCSI driver which was used automatically during my execises. But you may also need

update_drv -av -i '"scsiclass,01"' st

See also add_drv and rem_drv commands.