We've been seeing an issue where snapshots periodically fail for typically the same 2 or 3 VMs. 2 of them are almost retired Win2003 boxes but the 3rd is a 2008 R2 web application server. On all 3 of these when a snapshot fails the VM will lockup to the point where either I have to do a hard reset or HA takes care of it because it's lost the heartbeat. Once I moved the VM out of the protected LUN the lockups stopped.
Has anybody else seen this or have pointers? I'm running fully patched vSphere 5.5, both ESXi and vCenter and have a CS-300 with 10 GbE copper connectivity.