We recently deployed a Windows 2008 R2 VM in our environment. The server is also running Microsoft SQL and Microsoft SCCM. We have noticed that the server tends to hang or freeze every couple of days with no explanation. During the times it hangs, RDP is unavailable (hangs after accepting credentials), and the SCCM console (the whole purpose of this server) hangs as well. However, an inspection of resources (both inside Windows and in the VM enviroment) shows very little useage of memory or processor. The server also responds to pings and is very slow if a Windows session was already open. The only fix for the hang is to reboot the VM, OR to migrate the VM to a different ESX server. As soon as the migration is complete the VM is quickly active and responds as normal.
In our environment we have ESX5.0 cluster with 5 physical HP Blade servers (running HA) and attached to an HP 6000 SAN. We've been in this configuration for quite some time and run approximately 30 VM servers (mix of Windows 2003 and Windows 2008) with no performance problems. During peak times only 4 of the 5 ESX servers are actually running so I believe we are pretty efficient. During the times the server in question hangs, no other VM's appear to be affected and everything seems normal in the ESX cluster.
I've seen a few forum questions that were similar and related to video drivers, but that doesn't seem to be the issue here since the VM is running standard Microsoft display drivers. The VM is also running the latest compatible VMTools (8.6.5).
Any thoughts or suggestions as to what might be causing this hang? Thanks in advance for any assistance.