Linux – server reached pm.max_children setting (280), consider raising it

amazon ec2linuxnginxphp-fpmphp5

PHP-FPM process getting crashed in every few days due to reached pm.max_children, I have to manually start it to make the site up.

Server Configuration:

Total Memory: 7986M 
CPU: 2 Core
1 PHP Process Taking: 22M

PHP-FPM Configuration:

pm = dynamic
pm.max_children = 280
pm.start_servers = 15
pm.min_spare_servers = 15
pm.max_spare_servers = 35
pm.max_requests = 1000

Check the PHP-FPM log and found the following error.

[02-Aug-2017 23:23:54] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 10 idle, and 41 total children
[02-Aug-2017 23:24:04] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 0 idle, and 55 total children
[02-Aug-2017 23:24:05] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 16 children, there are 0 idle, and 63 total children
[02-Aug-2017 23:24:06] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 78 total children
[02-Aug-2017 23:24:07] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 93 total children
[02-Aug-2017 23:24:08] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 108 total children
[02-Aug-2017 23:24:09] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 123 total children
[02-Aug-2017 23:24:10] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 138 total children
[02-Aug-2017 23:24:11] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 153 total children
[02-Aug-2017 23:24:12] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 168 total children
[02-Aug-2017 23:24:13] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 183 total children
[02-Aug-2017 23:24:14] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 198 total children
[02-Aug-2017 23:24:15] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 213 total children
[02-Aug-2017 23:24:16] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 228 total children
[02-Aug-2017 23:24:17] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 243 total children
[02-Aug-2017 23:24:18] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 258 total children
[02-Aug-2017 23:24:19] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 32 children, there are 0 idle, and 273 total children
[02-Aug-2017 23:24:20] WARNING: [pool www] server reached pm.max_children setting (280), consider raising it

I can someone please suggest the best-optimized configuration for the PHP-FPM, Which can help to avoid the crashed.

What does this below line means:

[02-Aug-2017 23:23:54] WARNING: [pool www] seems busy (you may need to increase pm.start_servers, or pm.min/max_spare_servers), spawning 8 children, there are 10 idle, and 41 total children

Best Answer

Here's one suggestion for calculating the right number:

https://myshell.co.uk/blog/2012/07/adjusting-child-processes-for-php-fpm-nginx/

the following command will help us to determine the memory used by each (PHP-FPM) child process:

ps -ylC php-fpm --sort:rss

Then you take your server's available RAM and calculate:

pm.max_children = Total RAM dedicated to the web server / Max child process size

Also see:

php5-fpm: server reached pm.max_children

Related Topic