ASP.NET Application becomes unresponsive

Question

I make an application for querying from and inserting data to the database using ASP.NET 3.5 linq to SQL.

It works fine in the development server. But after deploying to the staging server, after the first few requests, the application seems unresponsive no matter what I type in the URL. The whole IIS application is frozen. I know I can restart the application to fix that. But I don't want it to happen again in the future.

What are the possible causes of this?

I've just found a ref about this problem:
http://blogs.msdn.com/lucascan/archive/2009/04/14/troubleshooting-an-unresponsive-web-server-iis-part-1-of-2-gathering-the-data.aspx

http://forums.iis.net/p/1154624/1893546.aspx

Answer 1

It's not easy to provide an exact cause since we have no idea how the application was written, what dependencies exist, whether service packs/patches are installed etc. What we could help with is debugging the application.

Things I would start with:

• Find out if other applications have the same problems.
• Review the server event logs on both servers.
• Memory, CPU usage etc on the server with Performance Monitor (perfmon.exe)
• See what SQL is being generated with SQL Profiler.
• Use an HTTP Analyzer like Fiddler to find out if the server is running anything in particular but the browser is not displaying it.

Answer 2

As BrianLy says this is one of those tricky to pin down situations. We had several problems with ASP.NET apps taking seemingly forever to start, this was down to our corporate firewall blocking crl.microsoft.com.

It's probably a stab in the dark, but it might be worth investigating. The chances of your issue being this sound slim though.

A quick test to see if it is something related to this is to add 127.0.0.1 crl.microsoft.com to your hosts file.