PHP at Density and Scale
Mixing performance, configurability, density, and security at scale has, historically, been hard with PHP. Early approaches have involved CGIs, suhosin, or multiple Apache instances. Then came PHP-FPM. At Pantheon, we've taken PHP-FPM, integrated it with cgroups, namespaces, and systemd socket activation. We use it to deliver all of our goals at unheard-of densities: thousands and thousands of isolated pools per box.
Watch how it's configured and see PHP-FPM pools start real-time to serve different Drupal sites as requests come into a server.
All of our tools for this are open-source and usable on your own virtual machines and hardware.