Had an issue on some new Server 2012 Hyper-V clustered hosts. Started seeing the following error in the logs:
Cluster Shared Volume 'SERVERNAME' ('') has identified one or more active filter drivers on this device stack that could interfere with CSV operations. I/O access will be redirected to the storage device over the network through another Cluster node. This may result in degraded performance. Please contact the filter driver vendor to verify interoperability with Cluster Shared Volumes. Active filter drivers found: ???????????????????????
Yes, those are random characters in the error message, so it’s difficult to track down the filter driver in question.
This seems to match the same issue in Server 2008 R2 – Redirected mode is enabled unexpectedly in a Cluster Shared Volume when you are running a third-party application in a Windows Server 2008 R2-based cluster
In the Microsoft KB notes, they state one of the conditions as being:
- The third-party application has a mini-filter driver that uses an altitude value to determine the load order of the mini-filter driver.
- The altitude value contains a decimal point.
Running fltmc.exe on these hosts shows the following filter drivers loaded:
The filter driver with the decimal point is stcvsm, the “StorageCraft Volume Snapshot Driver” The problem has only been occurring recently, after I installed ShadowProtect.
I’ve had to uninstall ShadowProtect from these servers until it’s officially supported on Server 2012. According to StorageCraft, that should be 90 days after the official launch date of Server 2012. That means there should be a new version of ShadowProtect around the 3rd of December 2012.