A very interesting talk by Scott Long on how they use FreeBSD for Netflix - ZFSers will be interested at the 22:00 mark where he explains why they didn't go for ZFS (they use UFS + journaling). They also don't use any virtualisation preferring highly tuned machines that avoid the overhead of virtualisation:
https://www.youtube.com/watch?v=FL5U4wr86L4
https://www.youtube.com/watch?v=FL5U4wr86L4