Failed Request Tracing is one of the most useful features in IIS 8.0. It enables you to gain detailed information about any page request and to be able to capture data based on the criteria that you define. This is not simply a tool for your development computer; this is a full-fledged, production-ready method of troubleshooting failures.
But what is even better is that as complex as it sounds, it really is not difficult at all. In the past, an IIS administrator would be required to rely on third-party tools to get inside the ASP.NET events to gain real-time insight into potential issues. These tools are usually expensive, have a steep learning curve, and often require a reset of IIS during installation. Tracing in some older versions of Windows Server brought the ability to see detailed debugging information free of charge and without installation downtime on the server, but the steps required to figure it out would scare the casual user.
With Failed Request Tracing in IIS 8.0, however, troubleshooting can be done at any time without downtime, with intangible performance overhead on the server, and with such ease of use that anyone can figure it out in a few minutes.
Failed Request Tracing was formally nicknamed FREB, or Failed Request Event Buffering, by the IIS development team. It is used to watch for all incoming requests that meet certain criteria and will save detailed information about the entire page request to disk in an easy-to-read XML format. ...