ZFS has a considerable number of very useful features that Btrfs doesn't have. For example, under ZFS, you can delegate administration of a filesystem (subvolum

ZFS has a considerable number of very useful features that Btrfs doesn't have. For example, under ZFS, you can delegate administration of a filesystem (subvolume in Btrfs terms) to a normal user. In doing so, you can, for example, set up each user's home directory as its own subvolume, allowing for per-account snapshots, and their own sets of subvolumes which can have differing properties as-needed. ZFS also has support in-driver for sharing volumes, which means nfs shares, and smb shares (unfortunately not under FreeBSD yet) work natively with the filesystem, and can be exported there, instead of needing to muck around with config files and then kicking things in the proper order. Btrfs is still Not There Yet for a lot of the advantages ZFS has over traditional filesystems. It has a some, and some are half-baked, like its offline deduplication, but is still missing a considerable number. Maybe in five years Btrfs will catch up, but it's not here now. Rearding licensing, the Linux kernel devs could also relicense to allow for cddl co-existence. Unfortunately, the petulance from such groups as the SFLC makes that very unlikely.