502 Gateway Errors under High Load (nginx/php-fpm)

Question

I work for a rather busy internet site that is often gets very large spikes of traffic. During these spikes hundreds of pages per second are requested and this produces rand

Answer 1

If it's not helping in some cases - use normal port bind instead of socket, because socket on 300+ can block new requests forcing nginx to show 502.

Answer 2

Unix socket accept 128 connections by default. It is good to put this line into /etc/sysctl.conf

net.core.somaxconn = 4096

Answer 3

@Mr. Boon

I have 8 core 14 GB ram. But the system gives Gateway time-out very often.
Implementing below fix also didn't solved the issue. Still searching for better fixes.

You have: fastcgi_buffers 4 256k;

Change it to:

fastcgi_buffers 256 16k; // 4096k total

Also set fastcgi_max_temp_file_size 0, that will disable buffering to disk if replies start to exceed your fastcgi buffers.

Thanks.

Answer 4

This should fix it...

You have: fastcgi_buffers 4 256k;

Change it to: fastcgi_buffers 256 16k; // 4096k total

Also set fastcgi_max_temp_file_size 0, that will disable buffering to disk if replies start to exceeed your fastcgi buffers.