Hello,
I am maybe jumping on an old-ish thread but what have you got as the HP Virtualstorage SAN solution exactly?
We've got HP StoreVirtual (ex HP Virtual SAN, ext HP Lefthand P4000 VSAN ex whatever name they use a the time) , and provided they are setup properly they are bullet-proof.
This is with VMWare 5.5, on 2 x DL380 using local storage + DAS, all local volume on RAID 5, and network RAID 0+1 for the logical volume + the FOM on a third VM Server.
You will have to have both RAID 5 to go down to loose your volumes which is unlikely if you monitor them carefully.
The down side of this setup is that you need 6 times the drive space (physical) than your actual usable space : that is the price of redundancy and resilience.
Finally, I would never run a virtual SAN on only one host, this would make it lost all its interest.
HP license is based on volume space if I am correct and you can have up to 3 hosts, unless this has change, they like to change name and licensing scheme on this product...
Depending on when it was bought, you may have a perpetual license (not longer the case with new licenses) for a certain number of host and unlimited volume.