Solved Add disk to existing raidz

tetsuo · Tuesday at 11:40 AM

Hello,
I've cloned the installation of FreeBSD to an external SD card and now I have another hard drive available for my RAIDZ configuration. This is the pool:

Code:

~ [prometheus] % zpool status stranger
  pool: stranger
 state: ONLINE
  scan: scrub repaired 0B in 00:14:48 with 0 errors on Thu Jan 30 14:31:57 2025
config:

        NAME        STATE     READ WRITE CKSUM
        stranger    ONLINE       0     0     0
          raidz1-0  ONLINE       0     0     0
            da1     ONLINE       0     0     0
            da2     ONLINE       0     0     0
            da3     ONLINE       0     0     0
            da4     ONLINE       0     0     0
            da5     ONLINE       0     0     0
            da6     ONLINE       0     0     0
            da7     ONLINE       0     0     0

errors: No known data errors

I want to add the da0 hard drive, I trued using zpool add:

Code:

~ [prometheus] % zpool add stranger raidz da0 da1 da2 da3 da4 da5 da6 da7
invalid vdev specification
use '-f' to override the following errors:
/dev/da1 is part of active pool 'stranger'
/dev/da2 is part of active pool 'stranger'
/dev/da3 is part of active pool 'stranger'
/dev/da4 is part of active pool 'stranger'
/dev/da5 is part of active pool 'stranger'
/dev/da6 is part of active pool 'stranger'
/dev/da7 is part of active pool 'stranger'

Is it possible to attach a new hard disk to the existing RAID without destroying the pool?

Seems like the only option I have is using zfs 2.3.0 but I only have zfs 2.2.6 running. Should I compile it?

Thanks

Emrion · Tuesday at 11:52 AM

I would try:
zpool add stranger da0

zpool-add(8)

tetsuo · Tuesday at 11:56 AM

Nope.

Code:

~ [prometheus] % zpool add stranger da0
invalid vdev specification
use '-f' to override the following errors:
mismatched replication level: pool uses raidz and new vdev is disk
~ [prometheus] % zpool add stranger raidz da0
invalid vdev specification: raidz requires at least 2 devices
~ [prometheus] % zpool add stranger raidz da0

I am trying compiling zfs 2.3.0. Which apparently has support for this.

Emrion · Tuesday at 12:08 PM

Ok. Seems the right command is zpool-attach(8), but the man page specifies it can't be a raidz vdev.

VladiBG · Tuesday at 12:12 PM

https://openzfs.org/w/images/5/5e/RAIDZ_Expansion_2023.pdf

You need to check in which version the expansion feature is included.

In the 15 - Current the man page is:

zpool-attach(8)

man.freebsd.org

And for 14.2-R and stable:

zpool-attach(8)

man.freebsd.org

tetsuo · Tuesday at 12:40 PM

>be me
>compile zfs 2.3.0 (https://openzfs.github.io/openzfs-docs/Getting Started/FreeBSD.html)
>gmake install
>reboot
>it works
>

Code:

zpool attach stranger raidz1-0 da0

>SHIT WORKS!

Any idea on how stable this could be?

Erichans · Tuesday at 2:29 PM

sukamu said:
Any idea on how stable this could be?

I have no experience with running RAIDZ expansion.

Having said that, RAIDZ expansion has been in the works for a considerable amount of time and OpenZFS Releases - overview shows that 2.3.0 is an official/full OpenZFS release, following a series of RCs up to zfs-2.3.0-rc5. It's just not landed in a supported FreeBSD version, such as stable/14 (14-STABLE) or in an upcoming releng/14.3 (14.3-RELEASE)

bob2112 · Wednesday at 9:03 PM

Emrion said:
I would try:
zpool add stranger da0

A long time ago I saw a dire warning about not typing that accidentally by missing out the word cache when adding L2 cache, because it results in a device with no redundancy being added to the pool. It also said that it's irreversible and requires the whole pool to be recreated from scratch. I think this was from old Oracle documentation, so it may have changed, but it's not something I'd want to try to see what happens.