Iis – Performance Counter for tracking 503 – Server Unavailable from IIS


I have an ASP.NET 4.0 Web Service running on IIS 6.0. I am trying to locate the appropriate Performance Counter to track 503 responses. I have limited "Web site connections" to 1 for testing purposes and have verified in my client that I am receiving a 503 – Server Unavailable.

According to Microsoft's documentation the ASP.NET\Requests Rejected counter specifically tracks 503 responses. I am not seeing this at all.

I have tried the following counters (all with scale set to 1 in the Performance graph) and none of them show any activity:

  • ASP.NET\Requests Rejected
  • ASP.NET v4.0.30319\Requests Rejected
  • ASP.NET Apps v4.0.30319\Requests Rejected
  • Active Server Pages\Requests Rejected
  • ASP.NET Applications\Requests Rejected

I have verified that other counters are tracking my web service activity properly (Web Service\Bytes Total/sec, ASP.NET Applications\Request Execution Time, etc)

Best Answer

Is it a new app pool with a custom identity? If so, make sure that your app pool identity is added to the IIS_WPG group. Otherwise it will throw the error you mentioned. It fails before it can log too, so that's consistent with your summary.

If it's not that, then test a test.html page to find out if it's .net related to app pool related.