I have a series of different servers all set up as VM's on 2 different hosts. Most of the servers were converted from physical boxes to VM's over the past couple of years. Lately we have begun to experience some problems within the different servers, and we think we've narrowed it down to connectivity issues. We're seeing intermittent disruptions in LAN communication between VM's that are on different hosts.

I'm not really sure where to start looking for the point of breakdown. The servers are all Windows OS's of one sort or another (Server 2003, Server 2008, XP, etc.). I hadn't made changes to the NICs from when the servers were virtualized, what should I look for there? If the VM's seem to be set properly, how do I test the hosts? They're both Dell PowerEdge servers with dual NICs, one's a PE2850, the other a PE2950. As far as I know they're both running with the latest firmware updates, although I could be wrong. Is there something to check through vCenter that could help me test the NIC's, or be sure I have the right driver/latest driver installed?

Any insight would be much appreciated.

If you migrate the problems onto the same host do the problem disappear? How are you seeing the network issues appear?

I've created a new VM on the same host as the SQL Server VM, and I don't see the issues in that VM, which at least narrows it down a bit. Still, I don't know if the problem is due to the original host & its hardware, or the original VM and its setup. I would like to be able to isolate the problem. If it's the host, I need to get it repaired. If it's the VM, I need to figure out how to re-configure in order to fix it.

The original VM is Windows Server 2003 SP2 (32-bit) and the Network Adapter as seen in the Device Manager is an "Intel(R) Pro/1000 MT Network Connection."

My log files from the program show the drop, and the program itself reports the "long call" to the SQL Server. That's when the problem happens.

EDIT: I didn't see the suggestion to migrate the VM, I will try that. That could help isolate the issue. I'll let you know what I discover.