Grow Multipath Block Device
Enlarging a multipath device
multipath -ll should show you:
# multipath -ll san4_Data
san4_Data (360002ac00000000000000dfa00004ca6) dm-3 3PARdata,VV size=250G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw `-+- policy='round-robin 0' prio=50 status=active |- 0:0:1:2 sdb 8:16 active ready running `- 1:0:1:2 sdg 8:96 active ready running
Or possibly, after peer persistence:
san4_Data (360002ac000000000000003bb0000d16e) dm-9 3PARdata,VV size=1.5T features='1 queue_if_no_path' hwhandler='1 alua' wp=rw |-+- policy='round-robin 0' prio=50 status=active | |- 0:0:1:2 sdg 8:96 active ready running | `- 1:0:1:2 sdq 65:0 active ready running `-+- policy='round-robin 0' prio=1 status=enabled |- 0:0:0:2 sdb 8:16 active ghost running `- 1:0:0:2 sdl 8:176 active ghost running
Also, dmsetup should give you something like this:
# dmsetup status san4_Data
0 524288000 multipath 2 0 1 0 1 1 A 0 2 0 8:16 A 0 8:96 A 0
One way to do this is to rescan the partition table for each device:
# blockdev --rereadpt /dev/sdg
But by far the quickest method is to rescan each SCSI device from the kernel. This is done with:
# echo 1 > /sys/class/scsi_device/2\:0\:0\:0/device/rescan
Either way, once the capacity changes you should see this in dmesg:
# dmesg
</nowiki>[4849955.387134] sdg: detected capacity change from 214748364800 to 322122547200</nowiki>
Having trouble? Try rescanning the entire scsi bus again with:
# echo "- - -" > /sys/class/scsi_host/host1/scan
Once you see the dmesg line, then resize the path in multipathd with:
# multipathd -k"resize multipath san4_Data"
Once that's done, multipath will now report the larger size:
# multipath -ll san4_Data
san4_Data (360002ac00000000000000dfa00004ca6) dm-3 3PARdata,VV size=350G features='1 queue_if_no_path' hwhandler='1 alua' wp=rw `-+- policy='round-robin 0' prio=50 status=active |- 0:0:1:2 sdb 8:16 active ready running `- 1:0:1:2 sdg 8:96 active ready running
Now you can proceed to enlarge the upper level components.
