This question may have been answered already but why is there downtime when I recycle an app pool? Is it because recycling restarts the app pool? I know that when recycling occurs, the worker process is restarted. I thought recycling causes uninterrupted service or am I mistaken?


Yes, restarting the Application Pool flushes the JIT cache as well as briefly takes the Pool offline from a user's perspective. This means that any active connections between the user and IIS are closed, and the user has to re-establish a connection.

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  • Thanks Trevor. I have a script that continuously pings one SharePoint site to check if it's up and running. If the ping fails, I receive an email of the error message and ping results for the SP site. I receive this error "Details: System.Net.WebException: The operation has timed out" and the ping results for the SP site are successful after my scheduled app pool recycle. For ex: my app pool is scheduled to recycle at 1:00am. I'll receive the error message and ping results at 1:01AM/1:02AM. The reason I recieve the error message may be due to the app pool recycle? – iamZel Jan 16 '14 at 13:57
  • yes, that's true. it took some time to sites came back after IIS reset. – Waqas Sarwar MVP Jan 16 '14 at 14:13
  • We wrote a warmup PowerShell script that is run after any IISRESET or app pool recycle so the first visitor doesn't experience the delay. The script does http GETs on several URLs. We make sure never to reset the app_pool (i.e. by editing the web.config) until off-hours. – Eccentropy Jan 16 '14 at 14:55
  • @Eccentropy Do you mind sharing that script? – iamZel Jan 16 '14 at 15:15
  • Fun fact: "Briefly" in 2013 obviously means a couple of minutes ;) – Robert Lindgren Jan 16 '14 at 15:19

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