Steps (7 total)
1. Extend the volume/LUN from the SAN management console
2. xe sr-list name-label= (note the uuid of the SR)
3. pvscan | grep [SR UUID] Note the device name (e.g. PV /dev/sdj )
4. echo 1 > /sys/block/device/device/rescan (e.g. echo 1 > /sys/block/sdj/device/rescan )
5. pvresize (eg: pvresize /dev/sdj)
6. xe sr-scan uuid=[SR UUID]
7. Verify that the XE host sees the larger physical disk: pvscan | grep [SR UUID]