If you’ve installed FreeBSD on one single Disk, but you want your OS Installation mirrored then have a look. In this example FreeBSD has been installed on da0 and a second disk has already been physically added.
Layout of the existing disk
# gpart show da0
=> 34 41942973 da0 GPT (20G)
34 6 - free - (3.0K)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 37744640 3 freebsd-zfs (18G)
41940992 2015 - free - (1.0M)
Layout of the zpool
# zpool status
pool: zroot
state: ONLINE
scan: none requested
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
gpt/zfs0 ONLINE 0 0 0
errors: No known data errors
Partition the new disk
# gpart create -s gpt da1
da1 created
# gpart add -t freebsd-boot -l gptboot1 -b 40 -s 1024 da1
da1p1 added
# gpart add -t freebsd-swap -l swap1 -b 2048 -s 4194304 da1
da1p2 added
# gpart add -t freebsd-zfs -l zfs1 -b 4196352 -s 37744640 da1
da1p3 added
# gpart show da1
=> 34 41942973 da1 GPT (20G)
34 6 - free - (3.0K)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 37744640 3 freebsd-zfs (18G)
41940992 2015 - free - (1.0M)
Attach the new disk to the existing pool and updating the bootcode on the new disk
# zpool attach zroot /dev/gpt/zfs0 /dev/gpt/zfs1
Make sure to wait until resilver is done before rebooting.
If you boot from pool 'zroot', you may need to update
boot code on newly attached disk '/dev/gpt/zfs1'.
Assuming you use GPT partitioning and 'da0' is your new boot disk
you may use the following command:
gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 da0
# gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 da1
bootcode written to da1
Verify the status
During the resilvering process
# zpool status
pool: zroot
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.
scan: resilver in progress since Thu Jun 15 19:52:54 2016
1.87G scanned out of 2.44G at 54.8M/s, 0h0m to go
1.87G resilvered, 76.66% done
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
gpt/zfs0 ONLINE 0 0 0
gpt/zfs1 ONLINE 0 0 0 (resilvering)
errors: No known data errors
Resilvering completed!
# zpool status
pool: zroot
state: ONLINE
scan: resilvered 2.44G in 0h0m with 0 errors on Thu Jun 15 19:53:45 2016
config:
NAME STATE READ WRITE CKSUM
zroot ONLINE 0 0 0
mirror-0 ONLINE 0 0 0
gpt/zfs0 ONLINE 0 0 0
gpt/zfs1 ONLINE 0 0 0
errors: No known data errors
Adding additional swap
I usually don’t mirror the swap.
# swapinfo
Device 512-blocks Used Avail Capacity
/dev/da0p2 4194304 0 4194304 0%
# swapoff /dev/da0p2
# swapinfo
Device 512-blocks Used Avail Capacity
Change /etc/fstab and start the service
# cat /etc/fstab
# Device Mountpoint FStype Options Dump Pass#
/dev/gpt/swap0 none swap sw 0 0
/dev/gpt/swap1 none swap sw 0 0
# service swap restart
# swapinfo
Device 512-blocks Used Avail Capacity
/dev/gpt/swap0 4194304 0 4194304 0%
/dev/gpt/swap1 4194304 0 4194304 0%
Total 8388608 0 8388608 0%