AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting
I've got a quite busy server: PHP (Wordpress) using W3TotalCache APC, Varnish for Apache and Cloudflare to handle all traffic. Ubuntu 14.04.4 LTS
Only one website with an average about 60k hits/day.
I get this message every now and then, few times a day. Has nothing to do with temporarily traffic spikes, we compared times with Google Analytics.
Thu Apr 28 14:14:42.938075 2016] [mpm_prefork:error] [pid 19137] AH00161: server reached MaxRequestWorkers setting, consider raising the MaxRequestWorkers setting
[Thu Apr 28 15:43:25.594147 2016] [core:notice] [pid 19137] AH00051: child pid 19866 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594313 2016] [core:notice] [pid 19137] AH00051: child pid 20386 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594407 2016] [core:notice] [pid 19137] AH00051: child pid 19143 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594498 2016] [core:notice] [pid 19137] AH00051: child pid 19144 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594572 2016] [core:notice] [pid 19137] AH00051: child pid 20597 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594642 2016] [core:notice] [pid 19137] AH00051: child pid 20395 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594704 2016] [core:notice] [pid 19137] AH00051: child pid 20424 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594785 2016] [core:notice] [pid 19137] AH00051: child pid 20598 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594870 2016] [core:notice] [pid 19137] AH00051: child pid 19861 exit signal Segmentation fault (11), possible coredump in /etc/apache2
[Thu Apr 28 15:43:25.594957 2016] [core:notice] [pid 19137] AH00051: child pid 19782 exit signal Segmentation fault (11), possible coredump in /etc/apache2
....
....
So I've increased MaxRequestWorkers first to 100, then 500, now its at 1024. But still happening.
This is my apache2.conf at the moment. Code:
<IfModule mpm_worker_module>
StartServers 256
MinSpareThreads 256
MaxSpareThreads 256
MaxClients 256
ServerLimit 256
ThreadLimit 256
ThreadsPerChild 256
MaxRequestWorkers 1024
MaxConnectionsPerChild 0
MaxRequestPerChild 1000
</IfModule>
There is a lot of free RAM, and load average is around 0.5, sometimes over 1. But never seen it higher then 2. So server seems healthy to handle the traffic.
top - 16:07:47 up 3 days, 18:18, 2 users, load average: 0.57, 0.46, 0.55
Tasks: 113 total, 1 running, 112 sleeping, 0 stopped, 0 zombie
%Cpu(s): 10.5 us, 2.0 sy, 0.0 ni, 87.4 id, 0.1 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 8176816 total, 2372560 used, 5804256 free, 189684 buffers
KiB Swap: 0 total, 0 used, 0 free. 1286692 cached Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
21930 www-data 20 0 337212 83308 60072 S 24.9 1.0 0:52.89 apache2
21945 www-data 20 0 327640 72684 58816 S 24.3 0.9 0:48.37 apache2
1182 nobody 20 0 702868 442268 83496 S 0.7 5.4 42:41.32 varnishd
Any ideas why Apache interrupts?
//j
Answer
Basically config got overwritten in: /etc/apache2/mods-available/mpm_prefork.conf
I put the new setting in that file and it seems Apache works correctly now.
Hopefully this helps someone else, don't put your config straight in apache2.conf or httpd.conf. Make sure you change all loaded config files.