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Expanding a multipath iSCSI storage on XenServer 6.2

February 7, 2015

We have everyone been there. Running out of storage. So new disks are installed and the iSCSI LUN has been increased. But in XenCenter the SR still shows the old size. So, what next?

First step is to get the updated size in the iSCSI layer. By using the fdisk utility you get the size of the disks in you environment:

fdisk -l /dev/sd[bdcefghi] 3>&1 2>&3

Replace the content between the brackets with the matching disks from you system.
In this example, /dev/sdh is the drive being expanded (and /dev/sdi since we are on a multipath system).

After taking note of the current size, run iscsiadm to get the updated size:

iscsiadm -m node -R

Running fdisk again should now show the new updated size. If not, no need to carry on reading this article…

Then we need to update the multipath layer. First run:

mpathutil status

locate the disk you are expanding, and note the scsi id, looking something like “3600000e00d1100000011219400020000” and then run

multipathd -k”resize map [scsi_id]” 

Running the mpathutil again should give you the new size.

Now lets update the LVM layer. Get the UUID of the SR, either from XenCenter or running:

xe sr-list name-label”xxxx”

Then get the device-name by using

pvs | grep [uuid]

And then resize it:

pvresize [device-name]

In my environment the device name was “/dev/mapper/3600000e00d1100000011219400020000”

Finally doing a rescan in XenCenter should give you the new size.

Thanks to “White Rooms Labs

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