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IIS 8.5 Application Pool 'Idle Time-out' Lagging IssueRSS

2 replies

Last post Jun 22, 2015 11:39 PM by dev4you

  • IIS 8.5 Application Pool 'Idle Time-out' Lagging Issue

    May 20, 2015 04:55 AM|dev4you|LINK

    IIS 8.5 seems to add an additional minute to the 'Idle Time-out (minutes)' setting and application pools get recycled 1 minute later as expected.

    Sample Configuration:


      <add name="DefaultAppPool" autoStart="true" startMode="AlwaysRunning">

      <processModel idleTimeout="00:02:00" />




      <site name="Default Web Site" id="1" serverAutoStart="true">

        <application path="/" applicationPool="DefaultAppPool" preloadEnabled="true">

          <virtualDirectory path="/" physicalPath="%SystemDrive%\inetpub\wwwroot\DefaultWebSite" />



          <binding protocol="http" bindingInformation="*:80:" />




    EDIT: After further testing, it seems the lag is triggered by the 'preloadEnabled' attribute being set to 'true'.

  • Re: IIS 8.5 Application Pool 'Idle Time-out' Lagging Issue

    Jun 20, 2015 12:40 AM|terridonahue|LINK

    That is likely caused by the fact that the first application pool will not recycle until the 2nd application pool is loaded and ready to take requests.

    Terri Donahue
    Microsoft MVP ASPNET/IIS

    Please 'Mark as Answer' if this post helps you.
  • Re: IIS 8.5 Application Pool 'Idle Time-out' Lagging Issue

    Jun 22, 2015 11:39 PM|dev4you|LINK

    Well, having the 'preloadEnabled' attribute set to true adds another minute to the timer and the recycle is delayed by 1 minute. So, if 'idleTimeout' is set to 20 minutes, the recycle kicks in after 21 minutes.

    Sure, the workaround is simple. Just lower the 'idleTimeout' by 1 minute (i.e. 19 minutes instead of 20 minutes) and the recycle kicks in as expected (i.e. after 20 minutes).