Adjusting child processes for PHP-FPM (Nginx)

When setting these options consider the following:

• How long is your average request?
• What is the maximum number of simultaneous visitors the site(s) get?
• How much memory on average does each child process consume?

Determine if the max_children limit has been reached.

• sudo grep max_children /var/log/php?.?-fpm.log.1 /var/log/php?.?-fpm.log