Adjust Apache ServerLimit and MaxClient

MaxClients actually tells the apache to allow this many concurrent clients.

Normally this limit is at 150. You can change this limit by editing your httpd.conf file.

httpd.conf is normally located at /etc/httpd/conf/httpd.conf

nano /etc/httpd/conf/httpd.conf

ServerLimit directive to let the value of MaxClients above 256 work.
By deafult ServerLimit is 256 (and is usually not already there in httpd.conf). If it is in your httpd.conf increase it above 256 or if it is not there add it in your httpd.conf

Press CTRL + W to find maxclients


Change MaxClients from 150 to any value below 256.

By Default MaxClients Maximum Value is 256.

If you want to increase it more above 256 you can do that but for that you need to follow the steps below.

You need to change the

ServerLimit 500

Now you can change your MaxClients uptop 500 

<IfModule mpm_prefork_module>

StartServers 5
MinSpareServers 5
MaxSpareServers 10
MaxClients 500
MaxRequestsPerChild 0
ServerLimit 500