Use the Edit Web Site Failed Request Tracing Settings dialog box to change previously configured tracing rules for failed requests.
UI Element List
Select this option to enable failed request trace logging for a specific site.
Type the path where you want to store the failed request trace log files.
Maximum number of trace files
Type the maximum number of failed request trace log files that you want to keep for the site. If no value is entered, the default maximum number of log files that will be stored is 50. When this limit is reached, new log files are created and older ones are removed.