Sometimes Apache stops responding and the error logs states the following

“[error] server reached MaxClients setting, consider raising the MaxClients setting

this indicates that the maximum number of clients that are allowed to connect Apache webserver has reached and you should consider raising the MaxClients and ServerLimit values.

The changes made in the Apache configuration file directly won’t work as cPanel look the new values in the file /var/cpanel/conf/apache/local. However, you can still make the changes directly in the Apache configuration and run the distiller to save the changes.

# pico /usr/local/apache/conf/httpd.conf

Set the new values i.e.

ServerLimit xxx
MaxClients xxx

and save the file. In order to make the changes permanent and make sure the changes don’t get overwritten on the next cPanel update, execute:

# /usr/local/cpanel/bin/apache_conf_distiller –update –main
# /usr/local/cpanel/bin/build_apache_conf
# /scripts/restartsrv httpd

Sometimes, you may receive the following warning message on restarting the Apache web service, for example:

WARNING: MaxClients of 500 exceeds ServerLimit value of 256 servers, lowering MaxClients to 256. To increase, please see the ServerLimit directive.

In such a case, make sure ServerLimit value  should be equal to OR greater than MaxClients.}