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We're running a Rails application under Passenger (via Apache) on an application server. There is a front-end web server (also running Apache setup as a proxy) in front of the application server. Sporadically, the connection between the web server and the application server on ports 80/443 dies, resulting in outages.

Nothing seems to trigger the outages - they don't happen on any kind of schedule that we can discern. The failures are eerily regular, though - they always last about 10 minutes (typically no less, sometimes as much as 12 minutes), and resolve themselves without any interaction. Restarting the Apaches and/or the Rails app seem to do nothing. There's plenty of RAM on the boxes. There is no firewall on the app server that would be blocking the inbound connections (this is all behind the proxy server and another firewall in front of that).

We're running out of things to check and need some ideas as to possible cause. Any thing that could be causing this?! Thanks!

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I have a similar issue in my server, but with no Apache proxy.

Do you have:

PassengerUseGlobalQueue on

in your /etc/apache2/mods-avaiable/passenger.conf?

My outages shows increasing requests on global queue, and when the app starts to respond again, after 5 to 10 minutes, there is no time request longer then 1000ms in production.log.

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