I had an issue yesterday which seriously affected the performance of an application based on SQL Server running on a Windows 2000 Server cluster.
clussvc.exe and lsass.exe, along with SQL were taking 100% CPU making the server so busy SQL could not respond to client requests.
We have established that there was no unusual activity on in terms of things running against the database, nor are there any issues with the hardware. Nothing unusual in the Event logs either. SQL was failed-over to the other node in the cluster, but within a few minutes that was in the same state. After about 4 or 5 hours the problem vanished, which is great until it comes back and we still don't have a 'fix'.
This is the only reference I could find with a Google, was this which pretty much matches our problem but there is no clear resolution.
clussvc.exe, lsass.exe take over cpu...sql processing stopped
Any help or suggestions greatly appreciated.