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I've migrated to php5-fpm on nginx setup ~2 months ago. Everything was fine until a few days ago, when I noticed my php websites not responding (the browser would simply just wait for data and eventually time out). Restarting php5-fpm helped. Here's the end of my /var/log/php5-fpm.log:

[09-Feb-2013 07:22:46] NOTICE: [pool www] child 26802 started
[09-Feb-2013 20:09:07] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[10-Feb-2013 07:22:40] WARNING: [pool www] child 5986 exited on signal 11 (SIGSEGV - core dumped) after 40414.794799 seconds from start
[10-Feb-2013 07:22:40] NOTICE: [pool www] child 13596 started
[11-Feb-2013 07:22:14] WARNING: [pool www] child 23530 exited on signal 11 (SIGSEGV - core dumped) after 36419.156740 seconds from start
[11-Feb-2013 07:22:14] NOTICE: [pool www] child 31088 started
[12-Feb-2013 06:25:07    [09-Feb-2013 20:09:07] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[10-Feb-2013 07:22:40] WARNING: [pool www] child 5986 exited on signal 11 (SIGSEGV - core dumped) after 40414.794799 seconds from start
[10-Feb-2013 07:22:40] NOTICE: [pool www] child 13596 started
[11-Feb-2013 07:22:14] WARNING: [pool www] child 23530 exited on signal 11 (SIGSEGV - core dumped) after 36419.156740 seconds from start
[11-Feb-2013 07:22:14] NOTICE: [pool www] child 31088 started
[12-Feb-2013 06:25:07] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[12-Feb-2013 07:22:34] WARNING: [pool www] child 20736 exited on signal 11 (SIGSEGV - core dumped) after 3448.720422 seconds from start
[12-Feb-2013 07:22:34] NOTICE: [pool www] child 23808 started
[13-Feb-2013 06:57:30] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[13-Feb-2013 07:21:48] WARNING: [pool www] child 13307 exited on signal 11 (SIGSEGV - core dumped) after 1459.134695 seconds from start
[13-Feb-2013 07:21:48] NOTICE: [pool www] child 13596 started
[13-Feb-2013 08:18:13] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[13-Feb-2013 11:14:49] NOTICE: Finishing ...
[13-Feb-2013 11:14:49] NOTICE: exiting, bye-bye!
[13-Feb-2013 11:14:50] NOTICE: fpm is running, pid 16123
[13-Feb-2013 11:14:50] NOTICE: ready to handle connections
[13-Feb-2013 15:21:53] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[14-Feb-2013 07:22:23] WARNING: [pool www] child 27208 exited on signal 11 (SIGSEGV - core dumped) after 17743.276891 seconds from start
[14-Feb-2013 07:22:23] NOTICE: [pool www] child 31521 started
[14-Feb-2013 15:21:33] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[15-Feb-2013 07:21:51] WARNING: [pool www] child 9699 exited on signal 11 (SIGSEGV - core dumped) after 36679.697975 seconds from start
[15-Feb-2013 07:21:51] NOTICE: [pool www] child 16671 started
[15-Feb-2013 09:35:35] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[16-Feb-2013 07:22:18] WARNING: [pool www] child 29553 exited on signal 11 (SIGSEGV - core dumped) after 22986.940724 seconds from start
[16-Feb-2013 07:22:18] NOTICE: [pool www] child 1459 started
[17-Feb-2013 07:21:42] WARNING: [pool www] child 10229 exited on signal 11 (SIGSEGV - core dumped) after 45737.338223 seconds from start
[17-Feb-2013 07:21:42] NOTICE: [pool www] child 18539 started
[17-Feb-2013 08:19:01] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[17-Feb-2013 22:27:30] NOTICE: Finishing ...
[17-Feb-2013 22:27:31] NOTICE: exiting, bye-bye!
[17-Feb-2013 22:27:31] NOTICE: fpm is running, pid 24139
[17-Feb-2013 22:27:31] NOTICE: ready to handle connections] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[12-Feb-2013 07:22:34] WARNING: [pool www] child 20736 exited on signal 11 (SIGSEGV - core dumped) after 3448.720422 seconds from start
[12-Feb-2013 07:22:34] NOTICE: [pool www] child 23808 started
[13-Feb-2013 06:57:30] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[13-Feb-2013 07:21:48] WARNING: [pool www] child 13307 exited on signal 11 (SIGSEGV - core dumped) after 1459.134695 seconds from start
[13-Feb-2013 07:21:48] NOTICE: [pool www] child 13596 started
[13-Feb-2013 08:18:13] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[13-Feb-2013 11:14:49] NOTICE: Finishing ...
[13-Feb-2013 11:14:49] NOTICE: exiting, bye-bye!
[13-Feb-2013 11:14:50] NOTICE: fpm is running, pid 16123
[13-Feb-2013 11:14:50] NOTICE: ready to handle connections
[13-Feb-2013 15:21:53] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[14-Feb-2013 07:22:23] WARNING: [pool www] child 27208 exited on signal 11 (SIGSEGV - core dumped) after 17743.276891 seconds from start
[14-Feb-2013 07:22:23] NOTICE: [pool www] child 31521 started
[14-Feb-2013 15:21:33] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[15-Feb-2013 07:21:51] WARNING: [pool www] child 9699 exited on signal 11 (SIGSEGV - core dumped) after 36679.697975 seconds from start
[15-Feb-2013 07:21:51] NOTICE: [pool www] child 16671 started
[15-Feb-2013 09:35:35] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[16-Feb-2013 07:22:18] WARNING: [pool www] child 29553 exited on signal 11 (SIGSEGV - core dumped) after 22986.940724 seconds from start
[16-Feb-2013 07:22:18] NOTICE: [pool www] child 1459 started
[17-Feb-2013 07:21:42] WARNING: [pool www] child 10229 exited on signal 11 (SIGSEGV - core dumped) after 45737.338223 seconds from start
[17-Feb-2013 07:21:42] NOTICE: [pool www] child 18539 started
[17-Feb-2013 08:19:01] WARNING: [pool www] server reached pm.max_children setting (10), consider raising it
[17-Feb-2013 22:27:30] NOTICE: Finishing ...
[17-Feb-2013 22:27:31] NOTICE: exiting, bye-bye!
[17-Feb-2013 22:27:31] NOTICE: fpm is running, pid 24139
[17-Feb-2013 22:27:31] NOTICE: ready to handle connections

The "Finishing..." lines are when I restarted php5-fpm service manually. I know it's not much info. Please tell me what else is needed.

What may be the problem?

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1 Answer 1

up vote 2 down vote accepted

You have two separate and distinct problems shown in this log.

  1. pm.max_children is set too low. This controls how many PHP processes will be spawned to handle simultaneous incoming requests. If more requests come in than children are available, the new connections have to wait... eventually they will wait forever. Raise this value; find it in /etc/php-fpm.d/www.conf.

    This is the actual cause of your immediate problem, though you have some more insidious problems which you probably haven't noticed yet...

  2. child ... exited on signal 11 means PHP is crashing while servicing requests. Depending on when in the processing it crashed, this may have no visible impact, or may result in blank pages, aborted transfers, users being mysteriously logged out, etc. Consider updating PHP to the latest point release (5.3.x or 5.4.x) and removing or replacing known problematic extensions such as APC.

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Thank you. I'm using 5.3.10 with APC. I have increased pm.max_children to 30. I'll watch the logs and see what happens. It's been quiet in the past 13 hours. –  muszek Feb 18 '13 at 11:54

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