A very quick summary of how I configured ZFS on my data center research machines with SmartOS. These are Dell PowerEdge R720xd's with PERC H710 controllers.
One thing to consider is that on install SmartOS will prompt you for disks to use for the zones zpool. If you select multiple disks they will be configured in RAID-Z1 by default. This will likely also work, but I wanted the additional performance and redundancy of a mirrored vdev zpool.
When prompted at install I selected c0t0d0 as the drive for the zones zpool.
Here is how I made it a mirrored vdev zpool:
zpool attach zones c0t0d0 c0d1t0
zpool add zones mirror c0t2d0 c0t3d0
Running zpool status shows the following:
scan: resilvered 4.00G in 0h0m with 0 errors on Fri Jan 18 01:11:15 2013
NAME STATE READ WRITE CKSUM
zones ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
c0t0d0 ONLINE 0 0 0
c0t1d0 ONLINE 0 0 0
mirror-1 ONLINE 0 0 0
c0t2d0 ONLINE 0 0 0
c0t3d0 ONLINE 0 0 0
This is very straight-forward. At some point I need to build a Chef Recipe for this.