If cluster issues due to disk level problems

1. Use default tools (disk management, perfmon,eventviwer,chkdsk etc) to analyze if any disk issues
2. Verify if any multipath issues - use disk management,MPIO drivers,iSCSI configuration
3. Disable cluster disk driver from device manager ,restart server & verify if disk visible in disk management.Restart server & re-enable cluster disk driver to troubleshoot further.
4. If disk signature specific errors in eventviewer ,Note down the signature for each disk,Restore it using DumpCFG ( windows 2003) or Diskpart - device ID (in windows 2008)