PHP PHP-FPM tuning: Using ‘pm static’ for max performance

Yes it's well known that pm = static is best for performance. It's what I use myself. But it will use the most memory as all PHP-FPM processes are in memory even if not used unlike ondemand or dynamic. Hence why Centmin Mod defaults to pm = ondemand in PHP-FPM config file at /usr/local/etc/php-fpm.conf

 

with PHP-FPM systemd service file in place see diff between pm = dynamic vs pm = static

For Centmin Mod 123.09beta01's defaults set in /usr/local/etc/php-fpm.conf for a 2 cpu, 4GB KVM VPS on CentOS 7

Code (Text):

;pm = ondemand
;pm = dynamic
pm = static
pm.max_children = 20
; Default Value: min_spare_servers + (max_spare_servers - min_spare_servers) / 2
pm.start_servers = 8
pm.min_spare_servers = 4
pm.max_spare_servers = 12
pm.max_requests = 5000

pm = dynamic has pm.start_servers = 8

Code (Text):

fpmstatus
Redirecting to /bin/systemctl status php-fpm.service
● php-fpm.service - PHP FastCGI Process Manager
   Loaded: loaded (/usr/lib/systemd/system/php-fpm.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/php-fpm.service.d
           └─limit.conf
   Active: active (running) since Sat 2019-01-26 18:20:54 UTC; 13h ago
 Main PID: 1987 (php-fpm)
   Status: "Processes active: 0, idle: 8, Requests: 11, slow: 0, Traffic: 0req/sec"
   CGroup: /system.slice/php-fpm.service
           ├─1987 php-fpm: master process (/usr/local/etc/php-fpm.conf)
           ├─1988 php-fpm: pool www
           ├─1989 php-fpm: pool www
           ├─1990 php-fpm: pool www
           ├─1991 php-fpm: pool www
           ├─1994 php-fpm: pool www
           ├─1995 php-fpm: pool www
           ├─1996 php-fpm: pool www
           └─1997 php-fpm: pool www

Jan 26 18:20:54 test.com systemd[1]: Starting PHP FastCGI Process Manager...
Jan 26 18:20:54 test.com systemd[1]: php-fpm.service: Supervising process 1987 which is not our child. We'll most likely not notice when it exits.
Jan 26 18:20:54 test.com systemd[1]: Started PHP FastCGI Process Manager.

pm = static only looks to pm.max_children = 20

Code (Text):

fpmstatus 
Redirecting to /bin/systemctl status php-fpm.service
● php-fpm.service - PHP FastCGI Process Manager
   Loaded: loaded (/usr/lib/systemd/system/php-fpm.service; enabled; vendor preset: disabled)
  Drop-In: /etc/systemd/system/php-fpm.service.d
           └─limit.conf
   Active: active (running) since Sun 2019-01-27 08:04:03 UTC; 2s ago
 Main PID: 15219 (php-fpm)
   Status: "Ready to handle connections"
   CGroup: /system.slice/php-fpm.service
           ├─15219 php-fpm: master process (/usr/local/etc/php-fpm.conf)
           ├─15220 php-fpm: pool www
           ├─15221 php-fpm: pool www
           ├─15222 php-fpm: pool www
           ├─15223 php-fpm: pool www
           ├─15224 php-fpm: pool www
           ├─15225 php-fpm: pool www
           ├─15226 php-fpm: pool www
           ├─15227 php-fpm: pool www
           ├─15228 php-fpm: pool www
           ├─15229 php-fpm: pool www
           ├─15230 php-fpm: pool www
           ├─15231 php-fpm: pool www
           ├─15232 php-fpm: pool www
           ├─15233 php-fpm: pool www
           ├─15234 php-fpm: pool www
           ├─15235 php-fpm: pool www
           ├─15236 php-fpm: pool www
           ├─15237 php-fpm: pool www
           ├─15238 php-fpm: pool www
           └─15239 php-fpm: pool www

Jan 27 08:04:03 test.com systemd[1]: Starting PHP FastCGI Process Manager...
Jan 27 08:04:03 test.com systemd[1]: php-fpm.service: Supervising process 15219 which is not our child. We'll most likely not notice when it exits.
Jan 27 08:04:03 test.com systemd[1]: Started PHP FastCGI Process Manager.

 

Yeah because static leaves PHP-FPM processes running even if idle and can have higher peaks due to handling more PHP work through more static PHP-FPM processes/children.