I actually own Two Virtuozzo 3 VPS license on two servers.
Running two cPanel VPS, one MySQL VPS and my personal VPS.
I wish that the cPanel VPS had a failover on the second server and be able to do "move" without downtime for hardware maintenance (I got almost none with Virtuozzo, but no failover).
Virtuozzo is not able to do that (failover and stuff), atleast, not build-in. So I was looking at XenServer, lastest free version offer that (and I'll save on SUS from Virtuozzo), but I need a shared storage. If I buy a shared storage, I'll have redundancy over my 2 VPS, cool ! But... I still have a single point of failure, if the shared storage crash all of my server goes down ? So I need a backup shared storage... damn $$ !
I think someone got a good idea (by searching on Google).
You just use SAN (most likely not to fail anyway, everythings is redundan) to put stuff and backup (rsync) your data localy (to the ESX or XenServer). If the SAN fail, you still have your data localy (with some backward, but well...) and you did provide a fast acces !