We have installed VM server 3.2.4 on a couple of servers and provisioned one RHEL 6 guest per physical. Every now and again the VM server appears to have a problem with multipathing and the attached LUNS go read only, so the guests crash. We did a default VM server install, with multipathing enabled, all our storage is SAN (emc vmax I think). When this last happened some other physical servers in the same enclosure had issues, basically they almost froze, but these servers did not crash or go read-only. I've had an SR on this, but supports answer was that we had a switch or SAN issue, nothing helpful. Any suggestions as to what I should look at? Thanks.
Personally, I would never run Oracle VM in production against an EMC array without using Powerpath. EMC arrays have long had issues with various linux distributions native multipathing.... Hence the existence of "EMC Powerpath".
Do the other servers you mentioned use powerpath.?