We UFS for content serving, and a mix of UFS and ZFS for boot/log/config filesystems.

We use UFS for content because we rely on zero-copy async sendfile for our high performance video serving data path. When using ZFS, sendfile is not async, and because ZFS uses ARC rather than the page cache, it requires a copy from ARC to network with ZFS, so its yet ready for our high performance workload.

We don't use RAID at all.