Attach mirror disk to zfs root disk

Copy partition table to the second disk...

prtvtoc /dev/rdsk/c1t0d0s2 | fmthard -s - /dev/rdsk/c1t1d0s2

bash-3.00# zpool attach rpool c1t0d0 c1t1d0
cannot label 'c1t1d0': EFI labeled devices are not supported on root pools.

Troubleshoot guide http://www.solarisinternals.com/wiki/index.php/ZFS_Troubleshooting_Guide

bash-3.00# zpool attach -f rpool c1t0d0s0 c1t1d0s0
Please be sure to invoke installboot(1M) to make 'c1t1d0s0' bootable.

bash-3.00# zpool status
pool: rpool
state: ONLINE
status: One or more devices is currently being resilvered. The pool will
continue to function, possibly in a degraded state.
action: Wait for the resilver to complete.
scrub: resilver in progress for 0h9m, 92.77% done, 0h0m to go
config:

NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
mirror ONLINE 0 0 0
c1t0d0s0 ONLINE 0 0 0
c1t1d0s0 ONLINE 0 0 0 5.95G resilvered

errors: No known data errors

apply the bootblocks after the second disk has resilvered.

# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c0t1d0s0

bash-3.00# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t1d0s0
bash-3.00# zpool status -v
pool: rpool
state: ONLINE
scrub: resilver completed after 0h10m with 0 errors on Mon Dec 21 18:51:08 2009
config:

NAME STATE READ WRITE CKSUM
rpool ONLINE 0 0 0
mirror ONLINE 0 0 0
c1t0d0s0 ONLINE 0 0 0
c1t1d0s0 ONLINE 0 0 0 6.42G resilvered

errors: No known data errors
bash-3.00# zpool status