FastCGI - also known as FPM ( FastCGI Process Manager ), is located at "
/etc/php5/fpm" . The configuraition files for each domain and for the global apache configuration (
www.conf ) are located at: "
/etc/php5/fpm/pool.d".
Be aware, that Plesk might overwrite changes, that you make in standard configuration files. If you would like to avoid this, rename the files in "/etc/php5/fpm/pool.d" to non-standard names like:
zzz.www.conf