We have 2 ESX 3.5 Update 4 servers with virtual center with 2 NICs in each server.
1 nic is dedicated to vmotion, service console, iscsi.
1 nic is dedicated to all virtual machine data traffic and heartbeat each with it's on vlan.
The 2 esx servers both have 2 FC ports connected to a fabric going to netapp.
There are 2 windows 2003 servers with SQL 2008 configured as a active passive cluster with MCSC. All drives are configured as RDM to the netapp.
To save on drive space on the Netapp, we configured an openfiler server over iscsi for backups.
What we've noticed is that whenever we perform backups over the iscsi network, our MCSC starts throwing event ID 1123 indicating the cluster nodes are missing heartbeats from the other (http://support.microsoft.com/kb/892422).
I've reviewed the configuration and can't see how iscsi traffic would affect the heartbeat network since they are on completely seperate switches. Has anyone encounter this before? We're starting to troubleshoot at every level right now but would like to see if anyone has encountered this before.
Thanks.
