title: IIS: FailedRequestTracing module failed to write buffered events to log file for the request that matched failure definition
body: <p>In my web Site I have enabled Failed Request Tracing log feature and configured it to store log files into
  the default folder %SystemDrive%\inetpub\logs\FailedReqLogFiles and I have set some failed request tracing rules.</p>
  <p>I have granted write permissions to that folder for application pool identity and I have checked that IIS_IUSRS account has write permissions as well on that folder.</p>
  <p>My web site is an ASP.NET MVC application that uses Web Garden configuration (application's pool is set to 4 worker processes).</p>
  <p>Log files are correctly stored in the folder but I get continuous warning messages in the event log like below:</p>
  <blockquote>
  <p>FailedRequestTracing module failed to write buffered events to log
  file for the request that matched failure definition. No logs will be
  generated until this condition is corrected. The problem happened at
  least %1 times in the last %2 minutes. The data is the error.</p>
  </blockquote>
  <p>It seems like the cause is that more than one worker process is trying to create a file log in the same folder so they are conflicting/collisioning when creating the next filename in sequence with a correlative number as explained <a href="https://forums.iis.net/t/1158660.aspx?Failed%20Request%20Tracing%20Event%202284" rel="nofollow noreferrer">here</a> by anilr.</p>
  <p>How can I solve this problem in order to avoid warning messages appear constantly in the event log?</p>
  <p>Note: I am using IIS 8.5.9600.16384 under Windows Server 2012 R2 Standard.</p>