It's the other way around. FB put a lot of investment into btrfs, but only for the features they needed. Single drive works great, because they needed that, b

It's the other way around. FB put a lot of investment into btrfs, but only for the features they needed. Single drive works great, because they needed that, but RAID-equivalents don't. On the flip-side, Sun->Oracle have spent decades investing in ZFS at all levels, and it's really solid now. Licensing is a minor issue with ZFS, but if you aren't distributing the code to others, those issues don't affect you.