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On my ubuntu 10.04 VPS, I get a regular 500 error on nginx (0.7.??)+ fcgi web server running a durpal site and when I trace the nginx error log I see plenty of these:

socket() failed: No buffer space available) while connecting to upstream ...,

I have tried differnt combination of configs but none fixed the problem. Currently I have 3 nginx workers, Keep-alive time out 15 seconds and and


I really appreciate if you Can you suggest a solution to this annoying problem.

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You are probably reaching your limit of RAM or of open sockets. Check the number of sockets with cat /proc/sys/fs/file-max and increase it with sysctl -w fs.file-max=[BIG NUMBER]

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your problem is in the upstream server, not in nginx, but I'm just guessing.

You can set your worker processes to 4 and then try

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Thanks, I tried your solution and will give the feedback. – alfish Dec 13 '10 at 20:26
No chance Gaurav, I still get the same error – alfish Dec 13 '10 at 20:34
You are exhausting a kernel resource. You should provide some basic information about what sort of system this is (is it a VPS? What OS?) etc – Gaurav Singh Dec 13 '10 at 20:52
Sorry I added the OS info at the topic. It is ubuntu 10.04. The Linux Kernel is 2.6.18-194 – alfish Dec 13 '10 at 21:09
Comments are correct, answer is not. This is a local kernel problem. – EJP Sep 8 '12 at 12:50

Add more RAM or free some system resources, to have allocable ram for system processes.

¿can you check free -mt or top, at the time that the error happens?

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