Protection of virtual machines on a Windows Server 2008 R2 Hyper-V cluster host fails with the error below after upgrading from System Center 2012 Data Protection Manager (DPM 2012) to System Center 2012 Data Protection Manager Service Pack 1 (DPM 2012 SP1). The same error will occur after a new installation of DPM 2012 SP1.
Affected area: \Backup Using Child Partition Snapshot\VM Occurred since: <date/time> Description: The replica of Microsoft Hyper-V \Backup Using Child Partition Snapshot\VM on VM.domain.com is inconsistent with the protected data source. All protection activities for data source will fail until the replica is synchronized with consistency check. You can recover data from existing recovery points, but new recovery points cannot be created until the replica is consistent. For SharePoint farm, recovery points will continue getting created with the databases that are consistent. To backup inconsistent databases, run a consistency check on the farm. (ID 3106) DPM is unable to continue protection for \Backup Using Child Partition Snapshot\VM on VM.domain.com because the change tracking information is corrupt (ID 30156 Details: The system cannot find the path specified (0x80070003)).
This occurs because DPM 2012 SP1 does not differentiate between a Windows Server 2008 R2 standalone or Windows Server 2008 R2 Clustered Hyper-V server and tries to use the dpmfilter bitmap. Due to limitations of the Windows cluster CSV 1.0 filter driver associated with Windows Server 2008 R2 Cluster Shared Volumes, the DPM 2012 SP1 dpmfilter driver is unable to perform the block level tracking of changes that is available when using CSV 2.0 on Windows Server 2012.
Perform the steps in the following procedure on each node of the CSV cluster to protect the data using the consistency check mechanism.
1. On the protected server, browse to the registry path HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft Data Protection Manager\Agent\2.0.
2. Create a DWORD registry value named ForceFixup and set it to 1.
3. Stop and then restart the DPMRA service.
DPM 2012 SP1 protection of virtual machines will now succeed but will revert to the behavior associated with DPM 2010 or DPM 2012. The backups will take longer to complete because we will now do block by block comparisons when performing a recovery point when protecting virtual machines on a Hyper-V Cluster host running on Windows Server 2008 R2. Enabling the ForceFixup registry value will produce the same results for other data sources hosted on the Windows Server 2012 computers where it is present. There is no way to apply this fix to only Hyper-V virtual machine protection.
NOTE: System Center 2012 Data Protection Manager Service Pack 1 introduced block level change tracking when protecting Windows Server 2008 R2 standalone or Windows Server 2012 Hyper-V standalone or clustered guests.