I have a lot of ASP.NET apps / websites on my server (Some custom built and some open source). I was wondering if there was a free (Or built into Win2003) way of finding out which applications use the most resources throughout the day?
Sort of a breakdown of CPU(s) & Memory... As I have a suspicion one of the open source apps is hogging the CPU from time to time?
I think Windows Perfmon is what you are looking for. Usually gives you everything you need in terms of process, overall usage etc etc. Covers just about everything, network, disk, memory and makes some nice graphs too. You can also export the results of the logging to CSV so you can build even nicer charts in Excel if you want.
Oh I forgot, I am not sure how to do this anymore, it was a long time ago, but you can also have your application publish counters to Perfmon. I did that in Java but I am sure that .Net will provided a way to do the same.
Windows 2003 includes a tool called Performance Monitor (perfmon.msc) which can keep track of various resources. It's a fairly powerful and complex tool, if you Google for "windows 2003" perfmon counters you can find a lot of information to get started and how to use it effectively.
Run your websites in different application pools, then you can isolate easily!
http://www.microsoft.com/technet/prodtechnol/WindowsServer2003/Library/IIS/67e39bd8-317e-4cf6-b675-6431d4425248.mspx?mfr=true tells how application pools work in IIS6