Hi I see in Exchange 2007/Windows 2008 Server Perfmon there is a counter for RPC Average Latency, but this seems to be per server. Is there any way to drill this down to per database/storage group? I assume that if the databases are held on seperate LUN's, then high RPC Latency for one DB wouldn't cause an increase in RPC Latency on another? Or would it?

There is no method, the rpc latency value will go up since it averages all rpc requests; however it doesn't mean that the latency affects all users, each rpc request is completely independendant, and each rpc request is not the same, some rpc requests may be more intensive then other rpc requests. If you're trying to validate whether or not the latency is affecting others you can use exmon to collect and measure the avg client latecy and compare with users in the slower disk group with the faster disk group.James Chong MCITP | EA | EMA; MCSE | M+, S+ Security+, Project+, ITIL msexchangetips.blogspot.com