Socket Activation Notes

gistfile1.txt

Socket activation:

NGINX=3:4

ListenStream=10646 (IPv6)
ListenStream=0.0.0.0:10646 (IPv4)
BindIPv6Only=ipv6-only

nginx.conf:
server {
  listen [::]:10646 ipv6only=on; #IPv6
  listen 10646; # IPv4 (Opposite of systemd - in systemd, specifying only a port will do v4.)
}

PHP tries to close out and clean up its socket unless you do a reload on it.

See http://freedesktop.org/wiki/Software/systemd/DaemonSocketActivation/#php-fpm for more information on this.

Pantheon is also using autofs/automount to mount its Valhalla files directory mounts.

Cron is done via drush, not using php-fpm at all.

Pantheon uses the CPUShares and BlockIOWeight cgroups for Pantheon. They are proportional distribution methods as opposed to nice, which is feast-or-famine. (A process with a high nice could use all the resources.)

Pantheon does not use MemoryLimit or MemorySoftLimit to limit php-fpm or MariaDB, and generally, the daemons themselves control it (e.g. via the php-fpm configuration.) Using MemoryLimit/MemorySoftLimit will send php-fpm processes into swap, which adds to overall load, which is unnecessary if there's system memory still available.