This video shows how to install a full ZFS system using bsdinstall, on FreeBSD 9.0-RELEASE. This is not like other tutorials where you just use the FreeBSD ISO as a live cd and then do everything manually, with this method you only have to set up the zfs zpool manually. The rest, user settings, network, time zone, etc is done by bsdinstall for your convenience.
The Z file system, developed by Sun™, is a new technology designed to use a pooled storage method. This means that space is only used as it is needed for data storage. It has also been designed for maximum data integrity, supporting data snapshots, multiple copies, and data checksums. A new data replication model, known as RAID-Z has been added. The RAID-Z model is similar to RAID5 but is designed to prevent data write corruption.