FPM

FastCGI Process Manager

Links

• Documentation
• Switching to FPM on Ubuntu/Debian

Monitoring PHP-FPM

• https://www.php.net/manual/en/fpm.status.php
• Zabbix monitoring php-fpm

HOWTO

Configuring number of servers

  dynamic - the number of child processes are set dynamically based on the
            following directives:
            pm.max_children      - the maximum number of children that can
                                   be alive at the same time.

            pm.start_servers     - the number of children created on startup.
                                   this value must not be less than min_spare_servers 
                                   and not greater than max_spare_servers.

            pm.min_spare_servers - the minimum number of children in 'idle'
                                   state (waiting to process). If the number
                                   of 'idle' processes is less than this
                                   number then some children will be created.

            pm.max_spare_servers - the maximum number of children in 'idle'
                                   state (waiting to process). If the number
                                   of 'idle' processes is greater than this
                                   number then some children will be killed.

FAQ

proxy_fcgi AH01071: Got error 'Primary script unknown'

The fcgi 404

AH01079: failed to make connection to backend: httpd-UDS

USB = Unix Domain Socket, look for logging/config about the socket involved