Memory Management ( > 25GB memory usage)

Belly nginx-forum at
Mon Jun 3 12:57:21 UTC 2013

Hello nginx!

I have one worker-process, which uses over 25GB memory (and doesn't stop to
do that).
My configuration is... let's say special:

So there is nginx, which proxies all requests to the PHP backend and the PHP
backend sends a large request back to nginx. I set the fastcgi_buffers very
enormous huge to avoid nginx creating temporary files on my disk - which
would result in high CPU load.

Here is my configuration: (reduced to the problem)

worker_processes 1;
worker_rlimit_nofile 80000;
worker_priority -20;

events {
        worker_connections 10240;
        multi_accept on;
# ... 
        # fastcgi settings
        fastcgi_buffers 20480 1k;
        fastcgi_connect_timeout 30;
        fastcgi_read_timeout 30;
        fastcgi_send_timeout 30;
        fastcgi_keep_conn on;
        upstream php-backend {
                keepalive 10000;

As you can see the buffers are extreme large, to avoid disk buffering. The
problem is that nginx doesn't free the buffers. It just eats and eats. I
know it's my fault and not nginx' fault. What am I doing wrong?

The response of my php backend could be from 1k to 300mb.

What is the best setting for my situation?


Posted at Nginx Forum:,239795,239795#msg-239795

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