random IIS session timeout

Question

I have a very strange problem and I am looking for any advice. I have a ASP.NET website running off of IIS 6 which works well for the most part. However, the sessions seem to be

Answer 1

Your asp.net application may be recycled. Recycling can happen if a memory or cpu threshold is reached, or after a while (15 min inactivity used to be the default on IIS6).

When the application is recycled, everything in memory is lost. It could be why you lose session data.

To make sure recycling is the culprit, you can look at the performance counter on your server, or just log something in the Application_Start global.asax handler.

For a list of asp.net performance counters on IIS6, check https://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/0a6c9f07-a70c-4c3d-b93d-5dfef593c744.mspx?mfr=true

The counters for "Application restarts" and "Worker process restarts" are the one you should be looking at.