“After loader support for ZFS was imported into FreeBSD around a month ago, I’ve been thinking of installing a ZFS-only system on my laptop. I also decided to try out using the GPT layout instead of using disklabels etc.
The first thing I started with was to grab a snapshot of FreeBSD CURRENT. Since sysinstall doesn’t support setting up ZFS etc, it can’t be used, so one have to use the Fixit environment on the FreeBSD install cd to set it up. I started out by removing the existing partition table on the disk (just writing zeros to the start of the disk will do). If you’re reading this before the january 2009 snapshot of CURRENT comes out , you have to create your own iso image in order to get loader with the latest fixes. Look in src/release/Makefile and src/release/i386/mkisoimages.sh for how to do this.
Then, the next step was to setup the GPT with the partitions that I wanted to have. Using gpt in FreeBSD, one should create one partition to contain the initial gptzfsboot loader. In addition, I wanted a swap partition, as well as a partition to use for a zpool for the whole system.
To setup the GPT, I used gpart(8) and looked at examples from the man-page. The first thing to do is to setup the GPT partition scheme, first by creating the partition table, and then add the appropriate partitions”
Step-by-step instructions can be found here (Lost in volumes – 16/12/2008)