This happens in our Production Web server. Sometimes the processor usage spikes to 100% and doesn't come down. The server hangs and we need to force it by doing an IISreset. The process that takes all 100% is w3wp.exe. IIS logs for this period looks normal with regular traffic. This has happened a couple of times already and appears to happen more frequently now. We are unable to find any pattern in this.
To solve this problem, we do an automated IIS Reset when the CPU spikes over 90%, this brings the processor back to normal.
Also, on this server, Active Session count is consistently around 4294958367(4 billion). Memory usage on the server looks normal though. When there is iisreset, the count goes down to 0 and comes back to this huge number in a few minutes.
There is only one website running on this server and the website has its own AppPool. Operating System: Windows 2003 Server R2 Enterprise Edition running IIS V6.0
What could be causing this?
Thanks..