I realize it's only recently become possible, via the new zfs raid-z vdev expansion feature:


Using Ubuntu 22.04.1 LTS (jammy) & OpenZFS via zfsutils-linux version 2.1.4-0ubuntu0.1 (as reported by dpkg -l | grep zfsutils). Use case is a home Samba NAS.

Starting with a 6 drive zpool pulled from an older machine (zpool import) and have run zpool upgrade -a

bob@nas:~$ zpool status
  pool: tank
 state: ONLINE
  scan: resilvered 1.46M in 00:00:02 with 0 errors on Wed Sep 21 12:06:07 2022

        NAME                        STATE     READ WRITE CKSUM
        tank                        ONLINE       0     0     0
          raidz2-0                  ONLINE       0     0     0
            wwn-0x5000c50063d584b2  ONLINE       0     0     0
            wwn-0x5000c50090e6b172  ONLINE       0     0     0
            wwn-0x5000c50063dde13d  ONLINE       0     0     0
            wwn-0x5000c50063d6e22c  ONLINE       0     0     0
            wwn-0x5000c50063d6b472  ONLINE       0     0     0
            wwn-0x5000c50063d965df  ONLINE       0     0     0

errors: No known data errors

Good so far...

I've added two additional drives to the system (total of 8), identical size & model to drives above. Linux sees the two added drives (for a total of 8) as sdf & sdg

I'd expected to expand raidz2-0 adding the two new disks via this cmd for each new drive:

bob@nas:/tank/public$ sudo zpool attach -f tank raidz2-0 {drivename}
cannot attach {drivename} to raidz2-0: can only attach to mirrors and top-level disks

What am I doing wrong here?



1 Answer 1


What am I doing wrong here?

This feature is not available yet nor in your version nor in current openzfs version.


  • Thanks for pointing that out!
    – Bob Levy
    Sep 22, 2022 at 15:12

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