We have an NT 4.0 Server (SP6a) which is running about 100 websites. Over the last few weeks on an almost daily basis the CPU hits 100% and stays there. The server slows to a crawl and there is nothing you can do but reboot.
It is the inetinfo.exe process which takes all the CPU and it happens during the day, never at night. This therefore leads me to the conclusion that one of our customers is running some rogue ASP code, not opening/closing DB connections properly or something else more sinister is going on (like a DOS attack).
I've tried using Performance Monitor to track down the problem but can't seem to find the right things to monitor to pin-point the source of the CPU drain. What should I be monitoring and once I identify threads/processes causing the cpu hit how do I then match them with the offending virtual site?