Last weekend I updated Exchange to SP2 and UR3 and have been keeping an eye on the server occacionally to make sure its running normal. Today I noticed in the Exchange Server Performance Monitor that there was a lot of spiking and more than normal activity. The extra activity was for the processing, so I went into the task manager to take a look at what process was using it all, as we normally run between 5-10% utilization on this server, and it was spiking up to 60% at times and consuming over 1GB of memory.
I checked out the Event Viewer and didn’t see any errors. There were quite a few warnings from ActiveSync for an iPad device for user dsims, could this be linked to the IIS process issue?
Next I downloaded Process Explorer and located the troubled process and gathered some more info. The IIS worker process was linked back to MSExchangeSyncAppPool. I went into the Performance Graph and noticed something odd, there was a lot of CPU usage and IO and then it stopped, and started again.
At this point, I did a google search for ‘MSExchangeSyncAppPool high memory usage’ and many pages linked back to an issue with iOS devices. Since I know who has the iPad in our company, I messaged them to see if they could take it offline for a while to see if that resolved the issue, which it did.
My concern is why was this process so heavily used? Was it a bug, was the user downloading all of their mail, what caused the issue?