You can perform the live disk REPLACEMENT if the server supports hot plug and rpool is mirrored.

Step:1 

OFFLINE the disk in zpool

# zpool offline rpool cxtxdx

Step:2 

Unconfigure the disk from OS level

# cfgadm -C unconfigure c1::dsk/cxtxdx

Step:3 

Physical replace the disk

Step:4 

Reconfigure the disk in OS level

# cfgadm -c configure c1::dsk/cxtxdx

Step:5 

Confirm that the replacement disk has an SMI label and a SLICE 0 to match the existing root pool configuration

Step:6

MAKING ZFS aware by using below command.

# zpool replace rpool cxtxdxs0

Step:7

Bring the disk in to zfs online.

# zpool online rpool cxtxdxs0

Step:8

Install the bootblock.

# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/cxtxdxs0

You can perform the live disk replacement if the server supports hot plug and rpool is mirrored.

Step:1 

Offline the disk in zpool

# zpool offline rpool cxtxdx

Step:2 

Unconfigure the disk from OS level

# cfgadm -c unconfigure c1::dsk/cxtxdx

Step:3 

Physical replace the disk

Step:4 

Reconfigure the disk in OS level

# cfgadm -c configure c1::dsk/cxtxdx

Step:5 

Confirm that the replacement disk has an SMI label and a slice 0 to match the existing root pool configuration

Step:6

Making ZFS aware by using below command.

# zpool replace rpool cxtxdxs0

Step:7

Bring the disk in to zfs online.

# zpool online rpool cxtxdxs0

Step:8

Install the bootblock.

# installboot -F zfs /usr/platform/`uname -i`/lib/fs/zfs/bootblk /dev/rdsk/cxtxdxs0