You might need to replace a disk in the root pool for the following reasons:

The root pool is too small and you want to replace it with a larger disk

The root pool disk is failing. In a non-redundant pool, if the disk is failing so that the system won't

boot, you'll need to boot from an alternate media, such as a CD or the network, before you replace

the root pool disk.

In a mirrored root pool configuration, you might be able to attempt a disk replacement without

having to boot from alternate media. You can replace a failed disk by using the zpool replace

command.

Some hardware requires that you offline and unconfigure a disk before attempting the zpool replace

operation to replace a failed disk.

For example:

# zpool offline rpool c1t0d0s0

# cfgadm -c unconfigure c1::dsk/c1t0d0

# cfgadm -c configure c1::dsk/c1t0d0

# zpool replace rpool c1t0d0s0

# zpool online rpool c1t0d0s0

# zpool status rpool

SPARC# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/c1t0d0s0

x86# installgrub /boot/grub/stage1 /boot/grub/stage2 /dev/rdsk/c1t9d0s0