We have configured nginx + haproxy + mongrels [ more than 150 instances]. While it works perfectly fine for small configuration, a larger set of mongrels - fail completely.

I have attached the configuration file for your reference. Apologies for the inconvenience if this is coming into the wrong list.

Each of those servers are 16G RAM, Quad Core, Dual Processor Machines by Dell. So - the memory shouldn't really be a problem.

Although someone did mention that ip_conntrack module might be a problem.

I am not sure what the issue is and not able to understand - why haproxy is unable to route requests.

Can you please tell me if there could be some other issue? All the servers are marked DOWN even through they're up

Nov 21 14:08:46 mw-server9 haproxy[323]: Server rails_proxy/mon170 is DOWN. 0 active and 0 backup servers left. 0 sessions active, 0 requeued, 0 remaining in queue.