We have a Hyper-V failover cluster running on Windows 2012 R2. Two of the VMs hosted by the Hyper-V cluster make up a virtual Windows failover cluster (2 VMs running Windows Server 2012 R2) hosting 2 instances of SQL Server. That cluster is configured to have one instance of SQL running on the first node and the other instance of SQL running on the second node. The current backup set is defined to backup the Hyper-V failover cluster VIP plus the cluster's physical nodes. The backup is failing with a V-79-40960-38521 when it attempts to backup the virtual Windows failover cluster VMs. Looking at the Application event log on the first VM, I can see that the VSS process is failing because it can't find a drive that is currently owned by the second VM. Any thoughts on how to backup up this configuration correctly?
Are you attempting to back up the SQL VMs as VMs? Instead of doing that, because the virtual agent doesn't know that they are clustered, back up the resource by it's Cluster name. You need to install the Backup Exec Agent on all the nodes of the SQL cluster. Once that is done, you should see the Cluster name as a resource on the Backup and Restore page. Select the cluster name and back up from there.