What is a pool in php-fpm?


In php-fpm, by default, immediately after installation, there is a www pool. Everyone knows about this and I hope they understand, but I'm not quite. Roughly I understand that this is a type of dedicated php-fpm process group. There may be probably several pools.

Can someone please explain or give a link to the documentation which explains what php-fpm pool is and why is it needed? I myself did not find it by googling.

Thank you in advance.


Php-fpm pools – allows you to run php processes under different users, thus creating a more secure environment. Also, for each pool – you can allocate your own resources and override php.ini variables

For example: For the production version of the site – one pool, for the development version of the site – another pool.

Each pool runs either on a separate port or on a separate socket file. According to some manuals on php-fpm optimization, it is wiser to use multiple pools for a site with high load.


In our experience, multiple upstream backends on the same machine, produce higher throughout than a single one.

Scroll to Top