Hello,
We are having an issue where IIS worker process (W3wp.exe) is using high CPU and server is struggling. In IIS, it's pointing out to MSExchangeRPCProxyAppPool. Users are then having issues with Outlook client as it freezes or keeps downloading emails. This mainly happens on our MB servers, and now occasionally CAS servers. If we put all traffic on one MB, then that MB suffers, so ended up putting tier one databases on a MB server that does not have high CPU. Our CPU usage used to average 30-40% and one Monday morning it just shot to 100%. Nothing was changed from our side, no updates, no new installations, nothing in event viewer pointing to this. We have tried recycling the MSExchangeRPCProxyAppPool, rebooting the servers, investigating layer 2 network, upgrading from CU19 to 22 and still we cannot find the reason from our investigations. Here is our setup:
- Exchange Server 2013 CU22, 96GB RAM, 12 processors @ 2.60 GHz
- Windows Server 2012
- 2 CAS servers
- 2 Live MB in two different locations in a DAG
- 3 Archive MB in two different locations in a DAG
Any help is greatly appreciated.