VDR users,
We recently switched our CIFS backup destinations from a Windows 2003 server to Windows 2008 R2 (SP1, 64-bit). Since that point, we had nothing but problems: nearly all backups were failing and corrupted, integrity checks always failed. I'm posting my resolution here so that others may find it and avoid the same issue.
The error shown in the VDR console was this:
Performance Tuning Guidelines for Windows Server ... - Microsoft
Namely on page 58:
TreatHostAsStableStorage
HKLM\System\CurrentControlSet\Services\LanmanServer
\Parameters\(REG_DWORD)
The default is 0. This parameter disables the processing of write flush commands from clients. If the value of this entry is 1, the server performance and client latency for power-protected servers can improve. Workloads that resemble the NetBench file server benchmark benefit from this behavior.
Change this setting to 1 and the server will accept Flush commands again from the VDR appliance. Since making this change (and rebooting) our VDR backups have been running smoothly again.
This should be noted in a KB item somewhere, so others won't have to lose any hair over it. Like one of these: