A PHP codes can be run on a web server using several SAPI (Server Application Programming Interface), one of which is PHP-FPM (FastCGI Process Manager).

PHP-FPM is an alternative PHP FastCGI implementation that has been extended with additional features to optimally serve higher traffic web pages. These features are:

• Creating an adaptive process
• Advanced process management with elegant start / stop functions
• Ability to run processes simultaneously in different uid / gid / chroot / environments and using different php.ini
• Logging of stdout and stderr (so that sensitive error messages do not appear on the web page, but can be routed to log files)
• Emergency restart in case of possible operator code cache destruction
• Accelerated Upload Support
• "slowlog" support - Logging unusually slow scripts (not only logs their names, but also stores their PHP backtraces and process run data).
• FastCGI extension such as fastcgi_finish_request () - a special function to complete the request and transfer all data to the client immediately (This allows time-consuming tasks to be performed without having to keep the client open).
• And many more ...

Although PHP-FPM was not originally virtual hosting designed (due to the large number of pools), yet is excellent for any application model.