I logged into vCenter Server today and looked at the VDR logs and it was riddled with errors.
It has the same errors for each VM that it's supposed to backup daily.
3/14/2012 6:30:56 AM: Normal backup using VM Backups
3/14/2012 6:31:02 AM: Failed to create snapshot for WHS11, error -3911 ( connect failed)
3/14/2012 6:31:09 AM: Task incomplete
However if I manually run the backup, it creates the snapshots with no issues and completed the backups with no problems.
I don't have to leave vCenter running for this to work as long as the VDR VM is runnign correct?
You need vCenter for doing the snapshots and for deleting them. So during the backup you can restart vCenter, but at the beginning and at the end of the backup of any VM you will need vCenter for doing the snapshots.