We’re experiencing over 100% CPU usage by one of our new instances, specifically the Prod.Client.WebCoreApp process. Yesterday it actually hit 117%!

Obviously whilst this happens, all 25 users cannot use Business central as it essentially times out under the load. Some will get a network disconnected error in their BC app screen.

Our go live day was Monday this week; the issue first started in the afternoon of day 2, with a full reboot being the only way to resolve. 

By the 3rd day, after disabling the Azure AAD functionality this dropped to only happening at 5:15, and was only then resolved by restarting the IIS twice.

We found an article relating to SPN and added SPN on Self permission to the account on the sever which runs the instance. 

Today being day 4, the issue didn’t happen agin until 4:45, whereby the same overloading of the CPU occurred. restarting the IIS again resolved it.

It’s the latest 2019 release, but 1 cumulative update is available i believe. The only reason we haven’t done this is because the test system didn’t have this issue.

This sever has two gold standard processors with plenty of RAM so physics performance should not be the issue.

Under test environment for the last 2 or 3 months, this was not an issue. The load throughout the day is absolutely fine with all users connected and it’s not until the end of the day this then occurs. Searching online for issues related to the service don’t yield any resolutions, hence my comment here for help.

on the processor monitoring it seems to ramp up from an average of about 6% usage to over the 100 for a few minutes; then takes a short dip before returning to 100 again, all causing such slowness for users that they simply cannot use BC.

interestingly the other two instances we are running do not have their process hitting such cpu heights. The other two are used for a web interface and the scheduler service.

any suggestions welcome.