Hi, Sometimes storage team needs to upgrade HBA and Storage. During that time some of the multipath may not active. In this circumstance, as a system administrator, It is safe to set the device offline manually instead of immediate disk path failure before any HBA and storage upgrade happen.
multipath -ll
mpathb (1IET 00010001) dm-2 IET,VIRTUAL-DISK
size=1020M features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 2:0:0:1 sdb 8:16 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
`- 3:0:0:1 sdc 8:32 active ready running
In this post I will use /dev/sdb for the disk operation. Setting the device offline disk: In this case I will set offline the /dev/sdb.
echo offline > /sys/block/sdb/device/state
Checking Disk State:
[root@node02 ~]# cat /sys/block/sdb/device/state
offline
In order to update multipath devices, we need to flush multipath and rescan it. (multipath -F; multipath)
[root@node02 ~]# multipath -F;multipath
Oct 18 23:00:35 | mpatha: ignoring map
create: mpathb (1IET 00010001) undef IET,VIRTUAL-DISK
size=1020M features='0' hwhandler='0' wp=undef
`-+- policy='round-robin 0' prio=1 status=undef
`- 3:0:0:1 sdc 8:32 undef ready running
multipath -ll
mpathb (1IET 00010001) dm-2 IET,VIRTUAL-DISK
size=1020M features='0' hwhandler='0' wp=rw
`-+- policy='round-robin 0' prio=1 status=active
`- 3:0:0:1 sdc 8:32 active ready running
After the storage and HBA operation we set the device running state again. Setting the device to running state.
echo running > /sys/block/sdb/device/state
[root@node02 etc]# cat /sys/block/sdb/device/state
running
Checking multipath after setting the device to running state.
[root@node02 etc]# multipath -ll -v2
size=1020M features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=enabled
| `- 2:0:0:1 sdb 8:16 active ready running
`-+- policy='round-robin 0' prio=1 status=active
`- 3:0:0:1 sdc 8:32 active ready running
Deleting a disk device Sometimes we do not need to a disk device. In this case we need to delete disk device. For safety It is highly recommended setting device to offline before deleting a disk device.
[root@node02 etc]# echo offline > /sys/block/sdb/device/state
Deleting the device
echo 1 > /sys/block/sdb/device/delete
[root@node02 etc]# fdisk -l /dev/sdb
If you want to add the disk again: Rescan the disk
echo "- - -" > /sys/class/scsi_host/host2/scan
dmesg output.
sd 2:0:0:1: [sdb] Attached SCSI disk
multipath -ll
mpathb (1IET 00010001) dm-2 IET,VIRTUAL-DISK
size=1020M features='0' hwhandler='0' wp=rw
|-+- policy='round-robin 0' prio=1 status=active
| `- 2:0:0:1 sdb 8:16 active ready running
`-+- policy='round-robin 0' prio=1 status=enabled
`- 3:0:0:1 sdc 8:32 active ready running