#!/bin/bash

# first disk reference from zpool status:
DISK_1=ata-HGST_HTS541010A9E680_JA1000102T3MZP

# second disk reference from /dev/disk/by-id
DISK_2=ata-APPLE_HDD_HTS541010A9E632_J88000HWGD8Z1B

# clone the original disk to give a bootable drive in the event of a failure
# and to shorten the resilvering process.
ddrescue \
    --force \
    --retry-passes=3 \
    /dev/disk/by-id/${DISK_1} \
    /dev/disk/by-id/${DISK_2} \
    ./logfile

# when cloning using ddrescue the zfs partitons have the same metadata as the original
# as shown by:
zdb -l /dev/disk/by-id/${DISK_2}-part2

# so we need to use: 
zpool labelclear -f /dev/disk/by-id/${DISK_2}-part2

# attach the partitions as mirrors:
zpool attach -f rpool \
    ${DISK_1}-part2 \
    ${DISK_2}-part2


echo "the resilvering process will begin now, you can see its progress with zpool status -v"