Somehow a Debian update broke bfs and I was getting this issue:
The ZFS modules are not loaded. Try running '/sbin/modprobe zfs' as root to load them.
To reinstall ZFS this worked for me – a compilation of many suggestions so not sure all were necessary but it worked:
apt-get clean apt-get update apt-get purge zfs* --get rid of everything ZFS apt-get remove spl dkms spl-dkms --get rid of more ZFS apt-get autoremove apt-get install -t jessie-backports zfsutils-linux --change to whatever your distribution uses --these commands recompile the libraries if they are still having issues dkms remove -m zfs -v 0.6.5.9 --all dkms remove -m spl -v 0.6.5.9 --all dkms add -m spl -v 0.6.5.9 dkms add -m zfs -v 0.6.5.9 dkms install -m spl -v 0.6.5.9 dkms install -m zfs -v 0.6.5.9