I have a strange intermittent connectivity problem happening about once every two weeks.
First my configuration: I am running a HyperV failover cluster with two physical hosts (node01 and node02). The hosts are both running Windows Server 2008 R2 HyperV server (the free one) with SP1. On those hosts I am running two VM's each running Windows Server 2008 R2 Web edition with SP1. My storage server is Windows Storage Server 2008 connected via iSCSI. Both hosts as well as the storage server are running the latest network drivers downloaded directly from Intel's website.
Here's the problem: 99.99% of the time, everything works perfectly. About once every two - three weeks, the VMs will both simultaneously lose network connectivity, both incoming and outgoing. When this happens,
- I cannot RDP into either VM.
- I can RDP into either host.
- I can connect to either VM from the Failover Cluster Manager by right-clicking on the node and selecting 'Connect to Virtual Machine'
- Once I connect to the VM as described in #3 above, I cannot get to any websites or machines on the LAN. Disabling and re-enabling the virtual network connection inside the VM doesn't fix the problem.
- If I move the VM to a different node, that fixes the problem (for the next two weeks).
- If I reboot the host and move the VM back onto it, that fixes the problem (for the next two weeks).
- When this happens, the failover cluster does NOT automatically failover the VM.
- There are no unusual event log entries on any of the hosts or VMs.
This has happened about 5 times with the same symptoms as described above. I suspect a network driver or network hardware issue, but since I'm already running the latest drivers I'm not sure what to do about it.
This is a real head-scratcher ... any ideas?
I found a very similar case here: Virutal Machine loses network connectivity on Hyper V Cluster
After installing hotfixes and updating network drivers, I am still experiencing the same problem. In response to the comment asking for hardware details, the server is an Intel SR1670HV, which is 1U chassis containing two independent S5500HV motherboards. Communication is via the motherboards' integrated NICs which are Intel 82574L. The network driver is version 126.96.36.199.