By default, DPM 2007 SP1 performs a backup of a Hyper-V Virtual Machine (VM) in an online state. However, DPM cannot back up a Hyper-V VM in an online state, if one or more of the following conditions are true:
Backup (Volume Snapshot) Integration Service is disabled or not installed.
VM has one or more dynamic disks.
VM has one or more non-NTFS based volumes.
The VM Cluster Resource Group in a cluster setup is offline.
VM is not in a running state.
A ShadowStorage assignment of a volume inside the VM is explicitly set to a different volume other than itself.
These conditions are set by the Hyper-V writer. In such a case, the VM is put in a saved state before a snapshot of host volumes are taken (except when the VM is turned off) for a backup. The Hyper-V writer adds the VM in the following format:
For offline backups: Backup Using Saved State\<VMName>
For online backups: Backup Using Child Partition Snapshot\<VMName>