Rescan SCST target on initiator

In case of disconnected SCST disk due I/O timeout, deleting disks and rescan SCST target is needed.

multipath -l shows status. 8:0:0:2 is <scsi_host, channel, id, lun>, 8:64 is disk id (0 - first, 16 second, 32 - third disk,...)

[root@node31.sit.cldn.eu ~]# multipath -l
mpathd (SSCST_BIOdrbd2_f6ec8e34) dm-4 SCST_BIO,drbd2
size=3.6T features='1 queue_if_no_path' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=0 status=active
| `- 8:0:0:2  sde 8:64  active undef running
`-+- policy='round-robin 0' prio=0 status=enabled
  `- 11:0:0:2 sdj 8:144 active undef running

At first, failing device has to be deleted:

echo 1 > /sys/block/sdd/device/delete

and SCST target (scsi host) has to be rescanned. Host number is available in the multipath -l list, see above:

echo "- - -" > /sys/class/scsi_host/host8/scan