FastCGIPHPFPM

FastCGI is a protocol that allows a web server to communicate with an external application process, known as an FastCGI application. PHP-FPM (FastCGI Process Manager) is an implementation of the FastCGI protocol for PHP. It is a highly efficient process manager that is particularly useful for busy websites and applications that need to handle a large number of requests.

When a web server receives a request for a PHP file, it can forward that request to PHP-FPM using the FastCGI protocol. PHP-FPM then manages a pool of PHP worker processes. These processes are kept alive and ready to execute the PHP script. Once a worker process has finished executing the script, it can be reused for subsequent requests, which significantly reduces the overhead associated with starting a new PHP process for every request. This makes PHP-FPM much faster and more efficient than traditional CGI or even mod_php.

PHP-FPM offers several advantages, including improved performance due to process pooling and reuse, better resource management, and enhanced security. It allows for fine-grained control over worker processes, including the ability to set the number of processes, manage their lifecycle, and configure them for specific needs. This makes it a popular choice for modern web development, especially in environments using web servers like Nginx or Apache with the event MPM.