We have several (15 or so) Hyper-V hosts running a number (126 or so) guests. We use DPM to backup our servers, but only a few of our VMs are backed up at the host level. Most are backed up as regular clients. I have been having trouble with a couple of the ones that we do backup at the host level and just got to looking for the answer to what is going on. Lucky for me I waited long enough for the Core Team to come up with some suggestions:
Ask the Core Team : DPM 2007 – Troubleshooting protection for Hyper-V
This post is about Windows Server 2008 with the Hyper-V role installed, that are being protected by System Center Data Protection Manager 2007. There may be one or many Virtual Machines on each Host/Parent Partition, and they may be running Windows 2003 and/or Windows 2008.