For the operating system, we use FreeBSD version 9.0. This was selected for its balance of stability and features, a strong development community and staff expertise. We will contribute changes we make as part of our project to the community through the FreeBSD committers on our team.
Web server
We use the nginx web server for its proven scalability and performance. Netflix audio and video is served via HTTP.
Routing intelligence proxy
We use the BIRD Internet routing daemon to enable the transfer of network topology from ISP networks to the Netflix control system that directs clients to sources of content.
ZFS is very stable on recent versions of FreeBSD, I can't speak for older versions as I don't have experience. I at least haven't had any issues with it and we use it in production.
It is an older version and not as feature complete as what you will find in Solaris.
ZFS doesn't use that much RAM if you don't turn on deduplication, which is of less use in a system that serves large compressed video files than one that handles tons of read/write traffic as an office file server.
Why would they use ZFS on a CDN? IIRC, ZFS has some performance characteristics that would make it a poor choice for something like caching data on a network edge when it's really designed for ensuring data integrity.
Operating System
For the operating system, we use FreeBSD version 9.0. This was selected for its balance of stability and features, a strong development community and staff expertise. We will contribute changes we make as part of our project to the community through the FreeBSD committers on our team.
Web server
We use the nginx web server for its proven scalability and performance. Netflix audio and video is served via HTTP.
Routing intelligence proxy
We use the BIRD Internet routing daemon to enable the transfer of network topology from ISP networks to the Netflix control system that directs clients to sources of content.