[CentOS] Proper partition/LVM growth after RAID migration

[Jay Leafey]

I just finished playing this "game", though with a SAN volume.  It took a couple of steps to take advantage of the extra space. 
First, the SAN manager extended the volume from 100G to 200G.  I idled everything referencing the drive by disabling the volume 
group ( vgchange --available n vgname ).  I then ran fdisk against the volume, noting the starting cylinder of the only partition on 
the drive.  I deleted the partition, recreated it using the same starting cylinder and let fdisk figure out the last usable cylinder 
on the drive, reset the partition type to LVM, and wrote the partition table.  At this point I had to reboot to get the system to 
re-read the partition table.  Once it came back up I used pvresize to extend the physical volume to use the additional space in the 
partition.  After that, vgdisplay showed the additional space as available for allocation.  This was complicated by the fact that it 
was actually a two-node cluster (RHCS and GFS) so I had to reboot both nodes before running pvresize.

I was originally just going take the easy way out by creating a second partition/physical volume to use the additional space, but it 
seemed inelegant.  I'm unlikely to ever extend this LUN more than once, but you just never know!
-- 
Jay Leafey - Memphis, TN
jay.leafey at mindless.com