What is PHP-FPM?

PHP-FPM (FastCGI Process Manager) is an alternative PHP FastCGI implementation with some additional features useful for sites of any size, especially busier sites.

These features include:

Adaptive process spawning (NEW!)

Basic statistics (ala Apache's mod_status) (NEW!)

Advanced process management with graceful stop/start

Ability to start workers with different uid/gid/chroot/environment and different php.ini (replaces safe_mode)

Stdout & stderr logging

Emergency restart in case of accidental opcode cache destruction

Accelerated upload support

Support for a "slowlog"

Enhancements to FastCGI, such as fastcgi_finish_request() - a special function to finish request & flush all data while continuing to do something time-consuming (video converting, stats processing, etc.)

... and much more.

It was not designed with virtual hosting in mind (large amounts of pools) however it can be adapted for any usage model.

它是一个进程管理工具。