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I'm wondering why my server has so many free apache slots open. The server only has a couple of busy and idle slots. Please look at the attached images for the amount of process used by the server versus our traffic.


  • Should I change my configurations so that there's less free slots?
  • If I do reduce the amount of free slots will it reduce the amount of memory the server is using?


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Which MPM are you using, and what is your configuration for that MPM? – Zoredache Aug 3 '12 at 23:35
@Zoredache Prefork. Configs: {StartServers: 8, MinSpareServers: 5, MaxSpareServers: 20, ServerLimit: 256, MaxClients: 256, MaxRequestsPerChild: 4000} – iDev247 Aug 4 '12 at 22:20
up vote 2 down vote accepted

You did not provide information on how idle slot/free slot and busy slot are computed on your graph. So I'll assume the following :

  • Busy slots are process/threads actually serving requests

  • Idle slots are process/threads created but not serving request

  • Free slots are process/threads that can be created before reaching max client.

Question 1 :

You should reduce max client only if you don't have enough RAM to handle all the HTTP requests you allow. For now, you can wait because "busy slot" never got above 100 so far.

Question 2 :

No. Apache uses more memory only when it spawns more process/thread.

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