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I see have an application which is using 40,000 handles. Could this be causing my system to become sluggish and unresponsive? What number of handles can Windows have before it becomes unstable?

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Everything I'm seeing says the limit is 10K, but you're well beyond that. So, clearly something has changed. – sysadmin1138 Aug 25 '10 at 16:52
"If you have to ask what the maximum is, you're probably doing it wrong" - TheDailyWTF – Chris S Aug 25 '10 at 17:17
Haha, good quote, I'm a huge The Daily WTF fan myself. – nbolton Aug 29 '10 at 12:50
up vote 5 down vote accepted

Microsoft's Mark Russinovich provides lots of these kinds of tests on his blog.

See Pushing the Limits of Windows: Handles

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From the article "Any process that has more than a ten thousand handles open at any given point in time is likely either poorly designed or has a handle leak" And I have to agree. – Chris S Aug 25 '10 at 17:16

Yes, this could easily be causing your system to become sluggish and unresponsive. Is it a homegrown application or commercial?

  1. Homegrown : fix the handle leak. Is something forgetting to close a file or TCP connection?
  2. Commercial : open a bug report and get that fixed.

For either, in the meantime, how long does it take for that many open handles to build up? Try restarting the process on an interval that won't affect your production environment, if you can.

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