To find out how many simultaneous connections your Apache server can handle, you need to check the configuration of the Multi-Processing Module (MPM), whether it is mpm_prefork, mpm_worker, or mpm_event. The number of allowed connections depends on settings like MaxRequestWorkers (previously known as MaxClients).

Steps:

  1. Open the Apache configuration file, usually located at /etc/apache2/apache2.conf or /etc/httpd/conf/httpd.conf (depending on your OS).
  2. Look for the MPM parameters:
    • For mpm_prefork:
      <IfModule mpm_prefork_module>
      MaxRequestWorkers 150
      </IfModule>
    • For mpm_worker or mpm_event:
      <IfModule mpm_worker_module>
      ServerLimit 16
      MaxRequestWorkers 400
      </IfModule>
  3. The MaxRequestWorkers parameter defines the maximum number of simultaneous connections Apache can handle. If you need to change this value, modify it in the configuration file and restart Apache:
    sudo systemctl restart apache2 # For Debian/Ubuntu-based distributions
    sudo systemctl restart httpd # For CentOS/RHEL-based distributions