80 concurent users = 502 gateway problem

[vladimir_ch]

Hi
every time after i receive number larger than 40 concurrent users my site starts returning 502 bad gateway

using nginx+php-fpm

I have tried many options including
proxy_buffer_size 128k;
proxy_buffers 4 256k;
proxy_busy_buffers_size 256k;

in the nginx config but nothing seems to work.

How do I increase the number of users that can access my site?

 

[InderS]

Hello,

I will suggest you please try to check your error logs files and let us know what exact error are you getting on in server error logs ?

 

[vladimir_ch]

Hello,

I will suggest you please try to check your error logs files and let us know what exact error are you getting on in server error logs ?

only this kind of error
2014/06/08 18:38:37 [error] 30933#0: *55067 connect() to unix:/var/www/vhosts/system/mysite.com/php-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream, client: 54.***.**.9, server: mysite.com, request: "GET / HTTP/1.1", upstream: "fastcgi://unix:/var/www/vhosts/system/mysite.com/php-fpm.sock:", host: "mysite.com"

 

[InderS]

Hello,

Can you please try to update your nginx config file with the following code.

send_timeout 120;
proxy_read_timeout 120;
proxy_connect_timeout 120;

 

[vladimir_ch]

Hello and thank you
however the problem still persists

some useful information from the load testing tool

HTTP 200 OK 0% (89)
HTTP 502 BAD GATEWAY 100% (25517)

The first timeout happened at 5 seconds into the test when the number of concurrent users was at 83. Looks like you've been rushing with a timeout of 1000 ms. Timeouts tend to increase with concurrency if you have lock contention of sorts.

more info about the problem at http://lowendtalk.com/discussion/28821/plesk-502-bad-gateway#latest