Hi everyone, I'm in the middle of an Exchange 2010 upgrade from Exchange 2003 and just started looking at performance graphs from the toolbox section in EMC. Over the past few days I have noticed that the "RPC Outstanding Requests" counter is slowly growing (almost at 40) and does not seem to be going down. The other two RPC Counters, "Averaged Latency " and "Latency Average (msec)" always stay below 10 which leads me to believe this is a configuration issue rather than a performance issue. Can anyone help me find where these outstanding requests are coming from and how to purge them? Thanks, Justin

If you are in the middle of moving data around, anything from perfmon counters isn't really going to be valid. I wouldn't even look at them for at least 48 hours after the last data move. It may well be down to the Exchange search indexer doing its thing as data is entering the database. Any number of things could be the cause, most of which aren't worth worrying about in the middle of a migration. Simon.Simon Butler, Exchange MVP Blog | Exchange Resources

That makes sense except that I haven't moved any mailboxes in the last 5 days. I still have one more group of mailboxes yet to be moved over but that's at least 3 weeks away. Do you still think the number should be coming down on its own?

See my post here http://social.technet.microsoft.com/Forums/en-US/exchange2010/thread/4c49ae6f-c403-4204-9c6e-6f5b1b804653 Very similar. Suggest you drill down into the RPC Outstanding requests rather than just looking at the total and see if you have the same as I have. Neill

Thank you so much. As soon as I restarted the mailbox replication service the counter dropped to normal levels. Microsoft should write a KB article on this as I'm sure other exchange admins are experiencing similar issues.

Welcome. I had Outlook hangs because of this. I'd done a lot of moves and the counter had got up to 416, must have been other pressure which took it above 500 and the server then throttled the clients. Or that is what it looked like anyway. :-) Neill