FREB Log file Formatter

IIS 7/7.5 has a module called Failed Request Tracing (aka FREB) using which we can capture a lot of valuable information in the modular pipeline within IIS. We in PSS use it quite often for troubleshooting various issues with regard to Performance, Authentication, custom Module/handler/ISAPI filter issues in the pipeline etc.

For more details on how FREB works here is a good link.

However you may notice that based on the rule that you configure with FREB you may end up with lot many log files that are generated by the FREB module. It again depends upon the number of requests hitting your website and how many of them fall under one of the rules that you have configured. The pain starts when you navigate to the folder where you have all these log files. The default location is %systemdrive%\inetpub\logs\FailedReqLogFiles\. If you have lot of log files created you may see them listed as below:


Looking at the above screenshot we know that the file names are not descriptive enough to help us distinguish which file corresponds to which request/property. It may be a little painful to go through all of them just to find the right one. Imagine 100+ files in the folder!

I have developed a simple application which asks you for the location where you have the FREB logs and then creates a copy of all the logs in a subfolder with more descriptive names. These names are actually based on the request properties associated with that log file like time-stamp, page name, verb, status code, time-taken etc.



After you run the tool it creates a subfolder named “NewFREBLogs” under the folder you selected above. It doesn’t modify or delete the existing FREB logs anyway.

The new file names will be more descriptive as shown below.



Hope this saves some time while rummaging through all the logs.

You can download it from the following link

Till next time…Cheers to life!