Working with a customer using Dynatrace there where some noticeable peaks in response times for a application that wasn’t highly used. As can be seen in the graph below:
The application was web based and hosted on IIS. I had come across problems like this before and suspected it was due to the idle timer setting for an application pool. By default IIS will shutdown worker processes after being idle for 20 minutes. However, for some applications the time to restart a worker process can be noticeable slow.
If you set the idle Time-out to 0 then it will not terminate and you won’t have to suffer the restart overhead. I have made this change several times and not seen any adverse affects. But remember all applications are different!