Inexplainable 2008 Failover Cluster Issues

Hi,

We have a 2008 Failover Node & Disk Majority SQL 2005 cluster.

There are 2 nodes in the cluster with 2008 Ent 64-bit SP2 installed.

At around 00:20 each morning we see various FailoverClustering errors in the event logs on both servers.

EventID: 1135, 1069, 1177

Before the FailoverClustering events are seen, 2 informational events appear regarding the 'Microsoft Failover Clustering Virtual Adapater'

EventID: 4201 'The system detected that network adapter Local Area Connection* 9 was connected to the network, and has initiated normal operation.'

This is causing the resources to failover to the secondary node.

I have run the Cluster Validation Wizard and everything passes. I have disabled the Windows Firewall service on both nodes.

We are presenting the storage via NetApp and the nodes have 3 nics installed

NIC1 - Server Vlan - Speed/Duplex Set to 1000Mb Full
NIC2 - Storage Vlan - Speed/Duplex Set to 1000Mb Full
NIC3 - Heartbeat - Speed/Duplex Set to 100Mb Full

Please can anyone help me troubleshoot these issues ?

Thanks

Scott