adding new drive to zfs raidz

pgee70

11/9/23, 2:22 AM

i have this raid set up:

root@zen:/dev# zpool status zfs-raid
  pool: zfs-raid
 state: ONLINE
status: Some supported and requested features are not enabled on the pool.
    The pool can still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
    the pool may no longer be accessible by software that does not support
    the features. See zpool-features(7) for details.
  scan: scrub repaired 0B in 12:38:49 with 0 errors on Sun Oct  9 13:02:51 2022
config:

    NAME        STATE     READ WRITE CKSUM
    zfs-raid    ONLINE       0     0     0
      raidz1-0  ONLINE       0     0     0
        sda     ONLINE       0     0     0
        sdb     ONLINE       0     0     0
        sdc     ONLINE       0     0     0

errors: No known data errors

i want to 'grow' this raidz array with some new disks (sdd and sde)

i have tried zpool attach zfs-raid /dev/sdc /dev/sdd but that gives and error: cannot attach /dev/sdd to /dev/sdc: can only attach to mirrors and top-level disks

i have also tried:

root@zen:/dev# zpool add zfs-raid /dev/sdd
invalid vdev specification
use '-f' to override the following errors:
mismatched replication level: pool uses raidz and new vdev is disk

2542

1 + 2

raid

hard-drive

zfs

matigo

11/9/23, 1:19 PM

Are the new disks the same size as the ones currently in the pool?

pgee70

11/10/23, 12:47 AM

yes they are i bought exactly the same model of disks as before. i decided to back up the data, nuke the pool and start again. that is working and only has about a day to copy left ! ;-)

Score:2

Ubuntu

freezed

11/10/23, 11:04 PM

TLDR: You cannot add devices to a RAIDZ.

This is an old limitation as mentioned by Dan Naumov in 2009

To reiterate, you cant just add a single disk drive to a raidz1 or raidz2 pool. This is a known limitation (you can check with SUN ZFS docs). If you have an existing raidz and you MUST increase that particular pool's storage capabilities, you have 3 options:

Add a raidz of the same configuration to the pool (think 3 disk raidz + 3 disk raidz or 5 + 5, for example)

Replace each (and every) disk in your raidz pool one by one, letting it resilver after inserting each upgraded disk

Backup your data, destroy your pool and create a new raidz pool with a bigger amount of disks.

But current docs still mention it:

zpool attach [-f] [-o property=value] pool device new_device

Attaches new_device to an existing zpool device. The existing device cannot be part of a raidz configuration. If device is not currently part of a mirrored configuration, device automatically transforms into a two-way mirror of device and new_device. If device is part of a two-way mirror, attaching new_device creates a three-way mirror, and so on. In either case, new_device begins to resilver immediately.

+ 1

pgee70

11/11/23, 12:23 AM

thanks - that is what i thought - looks like it has been a feature that has been asked for and is in development but not released yet. I just decided to nuke the pool and restore from backup.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: adding new drive to zfs raidz

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