IIS suddenly becomes unresponsive

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  Hi,
  
  ANTS Profiler runs its' application pool outside of IIS, so more than likely what has happened is that attaching the profiler made the website crash. Unfortunately, because of the design of IIS, we are unable to advise you about why it crashed because IIS hides all of its' error information and every time this happens we end up debugging it on a case-by-case basis.
  
  Your best bet is to check the application event log and see if w3wp.exe reports why it had to terminate.

  Brian Donahue April 30, 2012 05:53

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  You may also be able to get at least some data if you use the "fastest" profiling mode - the thing that causes the most issues with IIS is profiler's "line-level" code, which intrudes into assemblies and tries to get the metadata. This causes failures when the metadata has been scrambled up by obfuscators and/or code access policy denies the reflection permission.

  Brian Donahue May 02, 2012 06:48

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  You may also be able to find the source of the problem in IIS by enabling request tracing. This will create a series of logs in the IIS logs folder.
  
  First, you go to the server manager (or programs and features) and under ths IIS role->Health and Diagnostics, tick "Tracing".
  
  Then you can configure request tracing for the website.
  
  You should get details about every error in a separate log file in c:\inetpub\logs\FailedReqLogFiles.

  Brian Donahue May 09, 2012 06:17

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  Is there any chance that running a page request with hundreds of "Response.Flush()" in a short period of time will cause problems for the profiler? We have had such page running everytime we had crashes when profiling. Now when we have not used that page during profiling there hasn't been any problems.

  JamesO May 09, 2012 06:49

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  It wouldn't cause a problem for Profiler - profiler is agnostic to the code that runs 99.9% of the time. But the coding may be causing a problem that makes w3wp crash. I wouldn't presume anything unless there was some evidence, and like I said, most of this evidence gets buried by IIS.

  Brian Donahue May 09, 2012 07:16

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  What about long running (> 1 minute) page requests that does a lot of chruncing, including cpu and io? Could that be a problem for the profiler?

  JamesO May 09, 2012 07:45

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  Profiler shouldn't be ended by a long-running method.

  Brian Donahue May 11, 2012 10:32

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