Keeping your App Pools under control with IIS (CPU Monitoring)

IIS provides a built-in feature for monitoring and automatically restarting an app pool if a rouge process decides to consume a large amount of CPU time.

In order to set this up we should go to the IIS Console >> Server >> Application Pools and right hand click on the relevent application pool and hit 'Advanced Settings'.

From here we have a 'CPU' caption - we are looking at the following specific settings:

'Limit': Defines the threshhold for the 'Limit Action' will occur - this is measured in 1/1000 in % e.g. 100 would equal to a threhold of 10%.

'Limit Action': This settings defines what will happen when the 'Limit' threshold is reached - there are a few options to choose from: KillW3wp (restarts the application pool), Throttle (when 'Throttle' is set the app pool CPU time will be thorttled according to what is defined in 'Limit') and ThrottleUnderLoad (which is similar to the 'Throttle' option but only actually throttles when there is contention on the CPU.