It appears the XenServer 6.5 has been released and it's quite a bit faster than 6.2 in many ways.
When I installed 6.2 I accepted the various defaults and end up with a system that is awkwardly partitioned. Root is rather small (and perpetually running out of space) while a 250Gb partition sits empty. To this end I'm thinking about doing a rebuild with v6.5.
I've been reading about the process and apparently you can't mix 6.2 and 6.5 in the same pool. If I take the pool members (3) out one at a time, rebuild them and put them in a new pool can I move the various VMs over?
EDIT:
To upgrade XenServer from 6.2 to 6.5 - start with the pool master and work your way through each server. If you've done a repartition you don't have to do the editing steps again - as long as you select 'upgrade' during the 6.5 install it won't repartition the disks.