How to check if a website is reaching max_children in PHP-FPM

Question

My website is using PHP-FPM, and is timing out or loading slowly. How can I determine if it is reaching the max_children limit?

Answer

1. Access the command-line as the root user via SSH or WHM / Terminal.

2. Run the following command to find the available PHP-FPM logs:

   # find /opt/cpanel/ea-php*/root/usr/var/log/php-fpm/ -type f -name error.log

3. Run the following command on the log corresponding to the version of PHP your domain is using. PHP 8 is used in this example:

   # grep max_children /opt/cpanel/ea-php80/root/usr/var/log/php-fpm/error.log

Additional Resources

How to modify the max_children limit for PHP-FPM

Website frequently reaches the max_children PHP-FPM limit

Apache MaxRequestWorkers in relation to PHP-FPM max_children