ZFS root pool mirror

.1. Current state
#zpool status
  pool: rpool
  state: ONLINE
  scrub: none requested
  config:

        NAME        STATE     READ WRITE CKSUM
        rpool       ONLINE       0     0     0
          c1t0d0s0  ONLINE       0     0     0

#format
AVAILABLE DISK SELECTIONS:
       0. c1t0d0
          /pci@0,0/pci1000,8000@14/sd@0,0
       1. c1t1d0 |  new disk
          /pci@0,0/pci1000,8000@14/sd@4,0

2. Copy disk partition
#prtvtoc /dev/rdsk/c1t0d0s2 | fmthard -s - /dev/rdsk/c1t1d0s2

3. Attach
#zpool attach -f rpool c1t0d0s0 c1t1d0s0

4. Install grub in new submirro
#installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t1d0s0

Regards
Gurudatta N.R