It appears that the issue occurs on the cluster node where the physical disk resource did not come online.
@Unreason: Before this problem started did u install any security update for Symantec Endpoint Protection.
- Check the events are logged in the Windows Server
- Check the Cluster log.
If you figure out it is because of the Symantec update. The Solution is
Symantec has released a product to resolve this issue. The fix has been included in Symantec Endpoint Protection 11 RU6.
Note: SEP 11 RU5 was the first client with official support for Windows 2008 R2. Migrate up to SEP 11 RU6 to resolve this issue, or downgrade to SEP11 MR4 MP2 if your policies require you to test with the newly released support products before introducing them in your production environment. SEP11 MR4 MP2 can be installed to Sever 2008 R2, but you first must install Liveupdate (lusetup.exe), and then install the MR4 MP2 client.
Location to download Microsoft Handle tool - http://download.sysinternals.com/Files/Handle.zip