I planned to create a zroot mirror when I installed FreeBSD on the R720 but the supplier shipped only one of the two purchased SSDs.
Today the second drive arrived.
Let’s create a zroot mirror.
In this post:
- FreeBSD 12
- man 8 zpool
Posts I looked at:
- creating a mirrored ZFS Pool out of a single-disk rpool – not FreeBSD
- Convert Single disk ZFS-On-Root to Mirror – used the GUID via zbd; I figured I didn’t need to do it that way; I think I used their swap method.
- Converting a single disk ZFS pool into a ZFS mirror without rebooting – used rawuuid and I thought I could avoid that
- Adding a failed HDD back into a ZFS mirror – my old post, and it seemed to have what I needed now
Partitioning
In this section, the partition table for the second drive is copied from the first drive.
This is the existing boot drive. Let’s see what backup gives us:
[root@r720-01 ~]# /sbin/gpart backup ada0 GPT 152 1 freebsd-boot 40 1024 gptboot0 2 freebsd-swap 2048 4194304 swap0 3 freebsd-zfs 4196352 152104960 zfs0
This command copies it to the other drive, ada1:
[root@r720-01 ~]# /sbin/gpart backup ada0 | /sbin/gpart restore -F ada1
Let’s compare results:
[root@r720-01 ~]# gpart show ada1 ada0
=> 40 156301408 ada1 GPT (75G)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 152104960 3 freebsd-zfs (73G)
156301312 136 - free - (68K)
=> 40 156301408 ada0 GPT (75G)
40 1024 1 freebsd-boot (512K)
1064 984 - free - (492K)
2048 4194304 2 freebsd-swap (2.0G)
4196352 152104960 3 freebsd-zfs (73G)
156301312 136 - free - (68K)
[root@r720-01 ~]#
Labels! I forgot labels
Labels are not required. I do them.
I use the labels when I add the drive to the pool
I remembered how by reading Adding a zroot pool to an existing system.
Look at the labels on the existing drive:
[root@r720-01 ~]# gpart show -l ada0
=> 40 156301408 ada0 GPT (75G)
40 1024 1 gptboot0 (512K)
1064 984 - free - (492K)
2048 4194304 2 swap0 (2.0G)
4196352 152104960 3 zfs0 (73G)
156301312 136 - free - (68K)
Let’s duplicate that.
[root@r720-01 ~]# gpart modify -i 1 -l gptboot1 ada1
ada1p1 modified
[root@r720-01 ~]# gpart modify -i 2 -l swap1 ada1
ada1p2 modified
[root@r720-01 ~]# gpart modify -i 3 -l zfs1 ada1
ada1p3 modified
[root@r720-01 ~]# gpart show -l ada1
=> 40 156301408 ada1 GPT (75G)
40 1024 1 gptboot1 (512K)
1064 984 - free - (492K)
2048 4194304 2 swap1 (2.0G)
4196352 152104960 3 zfs1 (73G)
156301312 136 - free - (68K)
Before
This is zroot before:
[dan@r720-01 ~]$ zpool status zroot pool: zroot state: ONLINE scan: scrub repaired 0 in 0 days 00:00:03 with 0 errors on Thu Oct 10 21:37:16 2019 config: NAME STATE READ WRITE CKSUM zroot ONLINE 0 0 0 ada0p3 ONLINE 0 0 0 errors: No known data errors
Why am I not root? I because root because I had touble with that gpart copy command sequence. I should have gone back to my regular user earlier.
Add the second drive
The following uses an entry in /dev/gpt, which exist only because I added labels, using gpart. See a previous section.
[dan@r720-01 ~]$ sudo zpool attach zroot /dev/ada0p3 /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 [dan@r720-01 ~]$
Let’s see that status!
[dan@r720-01 ~]$ zpool status zroot pool: zroot state: ONLINE scan: resilvered 818M in 0 days 00:00:09 with 0 errors on Tue Oct 15 21:32:12 2019 config: NAME STATE READ WRITE CKSUM zroot ONLINE 0 0 0 mirror-0 ONLINE 0 0 0 ada0p3 ONLINE 0 0 0 gpt/zfs1 ONLINE 0 0 0 errors: No known data errors [dan@r720-01 ~]$
That didn’t take long at all!
Add that boot code
Now, remember to add that boot code. If you don’t, and you need to boot from that new drive, it won’t.
[dan@r720-01 ~]$ sudo gpart bootcode -b /boot/pmbr -p /boot/gptzfsboot -i 1 ada1 partcode written to ada1p1 bootcode written to ada1 [dan@r720-01 ~]$
Swap is next!
In my original FreeBSD install, I selected mirrored swap. Despite being a single drive, it did the right thing.
By that I mean:
geom_mirror.ko is loaded:
[dan@r720-01 ~]$ kldstat Id Refs Address Size Name 1 24 0xffffffff80200000 243d228 kernel 2 1 0xffffffff8263e000 27f48 geom_mirror.ko 3 1 0xffffffff82666000 3a9a10 zfs.ko 4 2 0xffffffff82a10000 a4f0 opensolaris.ko 5 1 0xffffffff82c22000 cc40 geom_eli.ko 6 1 0xffffffff82c2f000 1800 uhid.ko 7 1 0xffffffff82c31000 23a8 ums.ko 8 1 0xffffffff82c34000 acf mac_ntpd.ko
via this directive:
[dan@r720-01 ~]$ grep -r mirror /boot/loader.conf geom_mirror_load="YES"
Swap is active:
[dan@r720-01 ~]$ swapinfo Device 1K-blocks Used Avail Capacity /dev/mirror/swap.eli 2097148 0 2097148 0%
Everything looks good in the mirror:
[dan@r720-01 ~]$ gmirror status
Name Status Components
mirror/swap COMPLETE ada0p2 (ACTIVE)
Let’s add the new parition to this gmirror.
First, deactivate swap:
[dan@r720-01 ~]$ sudo swapoff /dev/mirror/swap.eli
Remember to turn that back on later.
Looking back to Creating a gmirror swap, I found:
[dan@r720-01 ~]$ sudo gmirror insert swap /dev/gpt/swap1
[dan@r720-01 ~]$ gmirror status
Name Status Components
mirror/swap DEGRADED ada0p2 (ACTIVE)
ada1p2 (SYNCHRONIZING, 25%)
[dan@r720-01 ~]$
By the time I was finished typing this, it was active:
[dan@r720-01 ~]$ gmirror status
Name Status Components
mirror/swap COMPLETE ada0p2 (ACTIVE)
ada1p2 (ACTIVE)
[dan@r720-01 ~]$
Turn swap back on
Now we turn the swap back on:
[dan@r720-01 ~]$ sudo swapon -a swapon: adding /dev/mirror/swap.eli as swap device [dan@r720-01 ~]$ swapinfo Device 1K-blocks Used Avail Capacity /dev/mirror/swap.eli 2097148 0 2097148 0% [dan@r720-01 ~]$
As is usual, that swap is defined via this entry:
[dan@r720-01 ~]$ cat /etc/fstab # Device Mountpoint FStype Options Dump Pass# /dev/mirror/swap.eli none swap sw 0 0 [dan@r720-01 ~]$
Hope this helps.
