Nginx & Passenger - failed (11: Resource temporarily unavailable) while connecting to upstream

Posted by Toby Hede on Server Fault See other posts from Server Fault or by Toby Hede
Published on 2011-03-03T04:49:01Z Indexed on 2013/10/20 15:57 UTC
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I have an Nginx and Passenger setup that is proving problematic.

At relatively low loads the server seems to get backed up and start churning results like this into the error.log:

connect() to unix:/passenger_helper_server failed 
(11: Resource temporarily unavailable) while connecting to upstream

My passenger setup is:

passenger_min_instances 2;
passenger_pool_idle_time 1200;
passenger_max_pool_size 20;

I have done some digging, and it looks like the CPU gets pegged. Memory usage seems fine passenger_memory_stats shows at most about 700MB being used, but CPU approaches 100%.

is this enough to cause this type of error?

Should i bring the pool size down? Are there other configuration settings I should be looking at?

Any help appreciated

Other pertinent information:

  • Amazon EC2 Small Instance
  • Ubuntu 10.10
  • Nginx (latest stable)
  • Passenger (latest stable)
  • Rails 3.0.4

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