Asked  7 Months ago    Answers:  5   Viewed   29 times

I have some error with subj. Server doesn't high loaded: ~15% CPU, there are several Gb of memory, HDD is not buisy. But error 502 throws approximately in 3% of cases.

Programs: Debian 6, nginx/0.7.62, php5-fpm (5.3.3-1).

In error.log of nginx is this error:

connect() to unix:/var/run/php5-fpm.sock failed

State of php5-fpm usually like this:

accepted conn:   41680
pool:             www
process manager:  dynamic
idle processes:   258
active processes: 1
total processes:  259

I think, this mean loading is not high.

I have increased backlog params: in sysctl - net.core.somaxconn = 5000, in php-fpm pool - listen.backlog = 5000. No effect.

I quote a configuration:


user www-data;
worker_processes  8;
timer_resolution 100ms;
worker_rlimit_nofile 20240;
worker_priority -5;

error_log  /var/log/nginx/error.log;
pid        /var/run/;

events {
    worker_connections  2048;
    use epoll;
    # multi_accept on;

http {
    include       /etc/nginx/mime.types;

    access_log  /var/log/nginx/access.log;

    sendfile        on;
    tcp_nopush     on;

    #keepalive_timeout  0;
    keepalive_timeout  65;
    tcp_nodelay        on;

    gzip  on;
    gzip_min_length 1100;
    gzip_buffers 64 8k;
    gzip_comp_level 3;
    gzip_http_version 1.1;
    gzip_proxied any;
    gzip_types text/plain application/xml application/x-javascript text/css;
    gzip_disable "MSIE [1-6].(?!.*SV1)";

    include /etc/nginx/conf.d/*.conf;
    include /etc/nginx/sites-enabled/*;

    client_max_body_size 100M;
    server_tokens off;


fastcgi_pass   unix:/var/run/php5-fpm.sock;
fastcgi_index  index.php;
fastcgi_param  SCRIPT_FILENAME  $document_root/$fastcgi_script_name;
fastcgi_buffers 256 128k;
#fastcgi_buffer_size 16k;
#fastcgi_busy_buffers_size 256k;
fastcgi_connect_timeout 300s;
fastcgi_send_timeout 300s;
fastcgi_read_timeout 300s;
include fastcgi_params;

php-fpm pool

listen = /var/run/php5-fpm.sock
listen.backlog = 5000
listen.owner = www-data = www-data
listen.mode = 0666
user = www-data
group = www-data
pm = dynamic
pm.max_children = 1024
pm.start_servers = 64
pm.min_spare_servers = 64
pm.max_spare_servers = 128
pm.max_requests = 32000
pm.status_path = /system/php5-fpm-status
slowlog = /var/www/log/php-fpm.log.slow
chdir = /var/www

What can I do to optimize this system and make this use all server resources?

PS. I'm sorry, my english is bad.



The issue is socket itself, its problems on high-load cases is well-known. Please consider using TCPIP connection instead of unix socket, for that you need to make these changes:

  • in php-fpm pool configuration replace listen = /var/run/php5-fpm.sock with listen =
  • in /etc/nginx/php_location replace fastcgi_pass unix:/var/run/php5-fpm.sock; with fastcgi_pass;
Wednesday, March 31, 2021
answered 7 Months ago

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.

Wednesday, March 31, 2021
answered 7 Months ago

Problem could be in the www.conf file. You are listening to but this way the service won't be reachable outside the container.

Try binding to

listen =
Saturday, May 29, 2021
answered 5 Months ago

Try to change default_type application/octet-stream; to default_type text/html; Maybe your php-script does not set a content MIME type and it goes from nginx.

Saturday, May 29, 2021
answered 5 Months ago

I figured it out

You need to add try_files $uri $uri/ /404.php?$args; to location ~.php$

No input file is specified because the file does not exist, and therefore is not passed. try_files $uri $uri/ /404.php?$args; checks that the file does actually exist, otherwise it redirects to 404.php

Saturday, May 29, 2021
answered 5 Months ago
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