https://github.com/MarcWeber/nixpkgs/commit/5d1f3e9d4cfe5da9950b94b05203cfa128c2b288 => see comments nixos/modules/services/misc/phpfpm.nix This code even figures out how many fpm daemons to start. Thus if you change ini (eg enabling xdebug) you'll get an additional daemon because you cannot use a pool for it. Marc Weber