Therefore, if you are able to retrieve, but encounter difficulty accessing, your site has likely reached your max_children limit. Note only web pages generated with PHP will suffer performance degradation as a result of your server hitting the max_children limit static files such as xml, text, and images will not be affected. When a browser’s requests remain backlogged in a queue, the browser typically shows a blank page or a “Waiting for data…” notification. If the volume of incoming requests requires the creation of more PHP-FPM processes than the number allowed by the max_children limit, those additional requests are backlogged in a queue to await service. Max_children refers to the maximum number of concurrent PHP-FPM processes allowed to exist in such a pool. Conversely, the manager destroys superfluous processes to conserve resources.

Should the amount of incoming requests surpass the current pool size’s capability to serve them, the process manager creates additional PHP-FPM processes. Typically, the size of these pools grows or diminishes to accommodate the volume of incoming requests. In order to allow for better concurrency and scaling, our servers use PHP-FPM, which allow pools of processes to simultaneously serve web requests that use PHP code. When responding to a web request, your server devotes much of its time to the generation of dynamic content. The PHP-FPM limit, often referred to as max_children, refers to the setting that designates the maximum number of concurrent PHP-FPM processes allowed to run on a server.

Php fpm workers