How to investigate sustained high CPU usage by Microsoft.Exchange.Rpc.ClientAccess.Service.exe

best practicescpu-usagedebuggingexchange-2010perfmon

One CAS server in our array has nearly 90% of its 4 CPUs used. The remaining CAS servers are at 30 percent.

How should I investigate what is causing this increase?

Below is a graph of:

  • Six (6) CAS servers serving 3,000 users in RPC/HTTPS (outlook anywhere) mode.
  • Windows 2008 R2
  • Recently upgraded to Exchange 2010 SP1 RU6 (same behavior on RU3)
  • Each CAS server has Four (4) Virtual CPUs

Points of interest

  • Since we asked our end users to configured Activesync against a different URL, we set up a dedicated VIP on the load balancer, and isolated the bottom two CAS servers. Doing this was easy… we changed the public DNS entry to facilitate the isolation. (I wish MSFT Best Practices would encourage an isolated URL for Activesync deployments)
  • The high CPU in black is coming from ActiveSync.
  • The green spike is from RPC Client Access service.

enter image description here

I ran MSFT's DebugDiag on the servers and don't know if that is the right tool to use, or what to do with some of the more advanced results. Any tips are appreciated.

Best Answer

See if this helps: http://social.technet.microsoft.com/Forums/nl/exchange2010/thread/55da7565-abc1-4c40-bade-7d3dc420de2e. Lots of possible causes are discussed there.

Related Topic