IIS 7 static file compression problem

Question

We have 3 web servers running IIS7. I've enabled compression for static and dynamic content. We have been testing the servers under heavy load and after half an hour the styles on the site started breaking.

I started investigating and found out that IIS was serving css and js files with Content-Encoding: gzip but the actual file content is not compressed. This cause the browsers to give error when trying to process the content. The issue disappears if I restart IIS.

Have anyone experienced a similar issues? What is the best way to diagnose the issue?

Thanks

Answer 1

The problem was caused by the CMS (sitecore) we were using. We upgraded to a later version and it has worked ever since. It's probably a 3rd party httpmodule causing the issue.