title: Apache+Passenger - Apache running; but not responding to requests
body: <p><strong>Background</strong></p>
  
  <p>I'm running a Ruby on Rails application that has to serve a lot of static files as well. </p>
  
  <p>My setup currently is:</p>
  
  <p>Debian Linux Lenny 5.0
   Apache 2.2.9
   Passenger 2.2.10</p>
  
  <p><strong>The problem</strong></p>
  
  <p>Everything runs fine. I see apache process spinning up, passenger instances get created and everything works fast and snappy. </p>
  
  <p>Then, after some time Apache does not respond to requests any more. Clients do get a connection and are "waiting for a response", but none comes.</p>
  
  <p>I cannot manually reproduce this problem. Sometimes it occurs a few hours after a restart, other times it takes a few days to happen. Here's what I found:</p>
  
  <p>Apache process are up; Passenger is there, but it does not have any instances spun up (probably because instances die after a period of inactivity)</p>
  
  <p>No error messages or problems in /var/log/syslog, /var/log/messages, not in apache's access and errors logs, not in my Rails production log. Nothing. </p>
  
  <p>When I stop and start apache everything is back to normal. </p>
  
  <p>Does any one have any clues what's happening here? And how it can be resolved? </p>