This was a bit of a strange thing to see on one of our clusters:
Log Name: System
Date: 1/8/2013 9:48:10 PM
Event ID: 5120
Task Category: Cluster Shared Volume
Cluster Shared Volume 'Volume4' ('CSV 04 XPVM-01') is no longer available on this node because of 'STATUS_CONNECTION_DISCONNECTED(c000020c)'. All I/O will temporarily be queued until a path to the volume is reestablished.
A search turned up the following:
- Microsoft KB: 2008795 Unable to access ClusterStorage folder on a passive node in a server 2008 R2 cluster
This KB talks about network connectivity with specific bindings for the adapters that the cluster uses for communication.
Well, we knew that we had the configuration on the NICs correct.
However, we were unable to ping via the Heartbeat network (Hyper-V Server 2008 R2 SP1) that was set on a separate tagged VLAN.
The problem ended up being found in the fact that their Gigabit switch had been recently replaced with a warranty replacement. We had missed the VLAN configuration when we set up the replacement switch.
Sure enough, a dig through the Failover Cluster Management console brought up the big red X on the Heartbeat Network.
And, ultimately we found out the reason why that setting was missed. Our network audit notes were not up to date on the VLAN setting for the Heartbeat Network.
In this case this mistake only caused a minor problem with cluster communication that redundant networking structures took care of in the cluster setup.
We cannot emphasize enough just how important it is to keep good a good audit trail of any and all client IT Solutions and their components.
Besides facilitating consistency across our solutions our clients have a working paper that will provide anyone with a very in-depth view of their network setup should the need arise.
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book