In this tutorial we’ll be optimizing the Apache server under VestaCP for better handling of requests, this will also speedup the site as requests are now handled more efficiently with this Apache MPM configs. By default under VestaCP Apache will be using mod_php and prefork mpm hence it is recommended to use prefork when using DSO.

Prefork MPM uses multiple child processes with one thread each and each process handles one connection at a time. So it is recommended to optimize the value rather than using Apache default config. This Multi-Processing Module (MPM) implements a non-threaded, pre-forking web server that handles requests in a manner similar to Apache 1.3. It is appropriate for sites that need to avoid threading for compatibility with non-thread-safe libraries. It is also the best MPM for isolating each request, so that a problem with a single request will not affect any other.

Lets get started with Optimization of Apache server under Centos and Ubuntu.

Centos :

Under Centos Open this file in editor:

nano /etc/httpd/httpd.conf
or
nano /etc/httpd/conf/httpd.conf

And add this configs at the end of httpd.conf :

KeepAlive Off
<IfModule prefork.c>
   StartServers        12
   MinSpareServers     10
   MaxSpareServers     30
   ServerLimit         512
   MaxClients          256
   MaxRequestsPerChild 3000
</IfModule>

Then restart apache server :

service httpd restart

Ubuntu :

Under Ubuntu Open this file in editor:

nano /etc/apache2/apache2.conf

Find and add/change this configs under apache2.conf file :

<IfModule mpm_prefork_module>
 StartServers        12
 MinSpareServers     10
 MaxSpareServers     30
 ServerLimit         512
 MaxClients          350
 MaxRequestsPerChild 3000
</IfModule>

Then restart Apache server :

service apache2 restart

Also check : How to Install PHP OPCache APC/APCu Memcached and Redis on VestaCP CentOS