Creating a mirrored root pool
With ZFS as your primary file system there is no need to mess around with RAID-controllers. To create a mirrored root pool (basically what you would expect from a RAID-1 configuration) figure out the exact pseudo files
root@chlodomer:~# format
Searching for disks...done
AVAILABLE DISK SELECTIONS:
0. c1t2d0
/pci@0,0/pci8086,2940@1c/pci1000,3091@0/sd@2,0
1. c1t3d0
/pci@0,0/pci8086,2940@1c/pci1000,3091@0/sd@3,0
2. c3t0d0
/pci@0,0/pci108e,5351@1d,7/storage@6/disk@0,0
Specify disk (enter its number): ^C
root@chlodomer:~#
and quit immediately pressing Control-C. In this case the two installed hard disks are represented by the pseudo files c1t2d0 and c1t3d0. Thus,
zpool attach rpool c1t2d0 c1t3d0