Discover new SCSI devices (LUNs) and multipath devices
LUNs on the storage cluster appear to the Linux host as SCSI devices, which are I/O paths that DM-Multipath aggregates into a new device, called a multipath device. The host does not automatically discover new SCSI devices (LUNs) that you add to your system. You must manually rescan them to discover them.
You must have a copy of the
rescan script, which is in the
sg3_utils package that is part of your Linux OS distribution.
Discover new SCSI devices (LUNs) and create the corresponding multipath devices for the LUNs:
Verify DM-Multipath configuration:
This displays the following type of output, listing the recommended settings for each NetApp LUN:
3600a0980324666546e2b443251655177 dm-2 NETAPP,LUN C-Mode size=10G features='4 queue_if_no_path pg_init_retries 50 retain_attached_hw_handle' hwhandler='1 alua' wp=rw |-+- policy='round-robin 0' prio=50 status=active | |- 0:0:1:0 sdb 8:16 active ready running | |- 0:0:0:0 sda 8:0 active ready running | |- 1:0:0:0 sde 8:64 active ready running | `- 1:0:1:0 sdf 8:80 active ready running `-+- policy='round-robin 0' prio=10 status=enabled |- 0:0:3:0 sdd 8:48 active ready running |- 1:0:3:0 sdh 8:112 active ready running |- 0:0:2:0 sdc 8:32 active ready running `- 1:0:2:0 sdg 8:96 active ready running