How to track IIS server performance

Question

I have a reoccurring issue where a customer calls up and complains that the web site is too slow. Specifically, if they are inactive for a short period of time, then go back to the site, there will be a minute-two minute delay before the user sees a response. (the standard browser is Firefox in this case)

I have Perfmon up and running, the cpu utilization is usually below 20% (single proc...don't ask). The database is humming along. And I'm pulling my hair out.

So, what metrics/tools do you find useful when evaluating IIS performance?

Answer 1

Hope this helps:
Best Practices for Speeding Up Your Web Site
Scaling Strategies for ASP.NET Applications
IIS Tuning
14 Rules for Faster-Loading Web Sites
Best practices for creating websites in IIS 6.0
Stanford Computer Cience - High Performance Web Sites
10 Tips for Writing High-Performance Web Applications
Writing High-Performance Managed Applications : A Primer
Nine tips for a healthy "in production" ASP.NET application
Speedy C#, Part 2: Optimizing Memory Allocations - Pooling and Reusing Objects
Memory Usage Auditing For .NET Applications
Troubleshooting HTTP Compression in IIS 6.0
Maximizing IIS Performance - 25 tips
Optimizing IIS 6.0 Performance
Page Speed - an open-source Firefox/Firebug Add-on
Performance Testing Guidance for Web Applications
Top 10 Performance Improvements in IIS 7.0
CHAPTER 6 Optimizing IIS 6.0 Performance
Performance Tuning Guidelines for Windows Server 2003 - Performance Tuning for IIS 6.0
ASP.NET Performance Tips
IIS 6.0 Tuning for Performance - by Peter A. Bromberg, Ph.D.
Improving .NET Application Performance and Scalability - by MS
Optimizing and Performance Tuning IIS 6.0
12 Steps To Faster Web Pages With Visual Round Trip Analyzer
Thread: IIS 6 performance tweak guide (draft)
CPU Settings for an Application Pool IIS6 e IIS7

Great improvements tips :
Running ASMX Web Services on STA Threads
Scale Net

Measure, measure, measure :
Load Test Your Site
Show Slow
Performance Monitor Wizard
Two Minute Drill: Introduction to XPerf
Suggested Performance Counters to Watch (IIS 6.0)

See what the best sites did :
Benchmarks
TOP 100

More resource :
Learn papers

My experience says:
- Enable compression (GZIP/Deflate) in IIS, for Static data. Simple to implement and with excellent results.
- if cpu is not your problem try to enable compression for dynamic data as well.

Answer 2

For your particular case, you need to increase the idle-timeout option in IIS because that delay is due to ASP.NET loading the binaries and starting your application. The default is 20 minutes, so if nobody accesses the site for 20 minutes, IIS will shut down the process and the next request will take a long time to start up.