Create a ZFS volume for Time Machine backup
From blinkenwiki
As root:
zpool create -o ashift=12 tank disk98 disk99 zfs set canmount=off tank zfs create -V 2T tank/backup diskutil erasedisk jhfs+ Zealot GPT disk100
At this point, Time Machine may ask if you want to use the new volume for backups. It's OK to say Yes and to choose the encrypt option.
To reverse this:
zfs destroy tank/backup zpool destroy tank