IIS5, 6, and 7 Speed Issues After Upgrade

Question

I will apologize in advance as this post is born out of severe frustration.

I have a classic asp website that has been running on Windows 2000/IIS5 for years, and another ASP.NET 2.0 site that we've recently started running on the same servers. So far, everything is running well.

Last year, I tried upgrading (fresh install) to Windows 2003/IIS6. The classic ASP site was much slower, about 50% slower based on logs/stats averaged over weeks of use. I tried everything to find out what was slow. Network tweaks. Integrated. Classic iis5 mode. In process. Out of process. Nothing ever made things better and I soon rolled back to IIS5/2000. The very day rolled back, performance went right back to where it was. This happened on more than one server. Eventually, I gave up and chalked it up to 2003 TCP issues of some sort.

I recently installed a Windows 2008/IIS server on a similar, but more powerful machine in hopes that things were better. Much to my happiness, my ASP classic app is faster under Windows 2008. Unfortunately, my ASP.NET app is 50-75% slower for now apparent reason. All of it's content loads. It's on the same network as the 2000 machine. The site was copied directly from the other machine, and it's a precompile web app from studio 2005.

While the page does hit the database and another server for initial data, it caches it from there for quite a while, it also uses the same db servers as the classic site, which is fast, so I know it's not necessarily a connection issue.

I've tried the default app pool and the classic .NET pool Made no difference. Upped./check the max threads, max per cpu in all the usual locations, web garen or no nothing seems to matter. I've double checked that the compilation debug=false is still set in the web.config.

For a quick benchmark, I used ab.exe (Apache Bench) to send 10 request, 1 at a time. Even if I use IE or Firefox to hit the site, it's clearly slower than under 2000, even according to firebug.

At this point, I'm frustrated and at a complete loss as to where to start. Has anyone been through this sort of mess before?

Answer 1

Speed depends on many factors. You do need to measure performance just on the server to understand if this is server issue. Enable tracing for your web site in web config and see which part/function is slowing it down. You can add you own tracing after each operation to see which block of code is slowest. I'm sure you will find things that you can improve/optimize once you which part of the page is the slowest.

Answer 2

In my case, the answer turned out to be simple one I fired up WireShark. There was 1 external resource request that could not be resolved since the test machine had no direct access to the internet like the live machine did.

It's always the little things.