This page is about ZFS-fuse, the ZFS attempt for Linux
ZFS is a filesystem.
I have abandoned this filesystem because it is about as closed as it can get without being officially closed. It's hampered by awkward licensing and patents making it intentionally incompatible with the GPL.
Even if it was made to work perfectly, running under FUSE is sub-optimal.
It also seems horrifyingly complex to use. Seriously.