IIS 6 and IIS 7, HTTP Error
New in IIS6 and IIS7 is the HttpErr which stores all the http errors encountered by IIS before it reaches the app, e.g timeout, user disconnect etc. However in IIS 6 and IIS7 there is no GUI to edit this property.
This is especially important in IIS7, since without knowing, your system drive may be having lesser and lesser space as more logs are stored
The following is an excerpt taken from msdn which gives you the reg key to update the http error folder so that you can move it somewhere else
|Registry Path: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\HTTP\Parameters|
|Data Type: REG_STRING|
|Default Value: systemroot\system32\logfiles|
|Specifies the location of the Httperr.log file. Httperr.log is a new feature in IIS 6.0. If HTTP.sys is unable to write an error to a Web site log because the request did not reach user mode, the error will be entered in Httperr.log. Errors that are written to Httperr.log include the following: 503 errors, idle connection time-outs, URL parsing errors, and the last 10 requests to a failed application pool.|