mpm_event increase MaxRequestWorkers with Plesk 12.5

[Jens Johansson]

Hi there,

with CentOS 7 and Apache 2.4, the Prefork MPM will be used by default, but with Plesk 12.5 it´s mpm_event.

Where is the configuration file for mpm_event with Plesk 12.5? I have only found a file for prefork:

• cat /etc/httpd/conf.d/mpm_prefork.conf
  # prefork MPM
  # StartServers: number of server processes to start
  # MinSpareServers: minimum number of server processes which are kept spare
  # MaxSpareServers: maximum number of server processes which are kept spare
  # ServerLimit: maximum value for MaxClients for the lifetime of the server
  # MaxClients: maximum number of server processes allowed to start
  # MaxRequestsPerChild: maximum number of requests a server process serves
  <IfModule prefork.c>
  StartServers 5
  MinSpareServers 5
  MaxSpareServers 15
  ServerLimit 100
  MaxClients 100
  MaxRequestsPerChild 4000
  </IfModule>

For mpm_event I have found nothing, neither in this forum nor with Google.

I want to increase the value "MaxRequestWorkers". I have seen the following errors in the LOG:[Wed Dec 16 17:15:31.156312 2015] [mpm_event:error] [pid 6756:tid 140608896264256] AH00485: scoreboard is full, not at MaxRequestWorkers

 

[IgorG]

BTW, you can try to switch fpm to prefork with optimization_settings command. More detail:

# plesk bin optimization_settings --help

 

[Jens Johansson]

Hi Igor,

this means that you do not know where we can change the configuration ?

Odin writes regarding prefork and event (http://docs.plesk.com/release-notes/12.5/upgrade-notes/):

• (Plesk for Linux) Websites using the Apache module PHP handler do not work on Plesk for Linux servers with Apache 2.4 installed due to the ‘event’ MPM being used in Apache 2.4.

Are you sure that we should use prefork?

 

[IgorG]

this means that you do not know where we can change the configuration ?

Initially you have default mpm_event configuration. If you need to customize this default configuration you should create config file /etc/httpd/conf.d/mpm_event.conf with needed options. Something like

<IfModule mpm_event_module>
MaxRequestWorkers xxxx
</IfModule>

 

[Jens Johansson]

Hi Igor,

many thanks. I assumed, that already one exists. In Plesk 12.5 is Event "enabled by default" and the default value 16/25 (https://httpd.apache.org/docs/2.4/en/mod/mpm_common.html) is very low.

I will create a customize config file, however with:

<IfModule event.c>
StartServers 5
MinSpareThreads 25
MaxSpareThreads 75
ThreadsPerChild 25
ThreadLimit 65
MaxRequestWorkers 100
ServerLimit 100
MaxConnectionsPerChild 1000
</IfModule>

We have roughly 10Gig RAM . Do you see any problems?