II7 introduced a new troubleshooting tool called Failed Request Tracing. This will provide detailed error messages as well as what may be causing a site to load slowly. This can be enabled on a site by site basis. It uses a simple wizard to create and edit the various rules but supports a lot of features to help in detecting site problems. Amongst it's capabilities are:
- Monitor requests to any file type you specify, including .asp, .aspx and .php.
- Check full request and response HTTP headers to make sure all required data is available.
- Calculate how many bytes were sent back and forth, and how long it took to process the request in each pipeline step.
- Filter on requests that take over N seconds to process.
- Filter on certain HTTP response codes, such as 403, 404 or 500.
- Filter on filenames with wildcards, such as "login*.aspx".
- Know which HTTP modules were used to handle the request.
- See how routing and URL rewriting affect request processing.
- Monitor which application pools were used to handle the request.
- See how load balancing (if enabled) is working and which server is responding to the request.
- Select the appropriate providers for tracing events, such as web server caching, compression, ASP.NET infrastructure, and so on