I have a ZFS Raidz pool with 3 drives. When I setup the pool I set it up with 6 slots. I am now attempting to add another 20TB drive to expand storage and I am encountering an error. Is there no way to expand a ZFS pool in unraid? I am running 6.12.6. The current pool is over 70% full and way larger than my main array so I have no way to back this up and recreate a new pool.

 

Help Please 🙏

I did some more research and it looks like this functionality is very new. Maybe this is a case where unraid needs to implement a new version of ZFS? https://github.com/openzfs/zfs/pull/15022

That functionally should work, please post the diagnostics.

Here are the diagnostics!

blackbird-diagnostics-20240207-1031.zip

I'm sorry, I didn't read the 1st post correctly, you cannot expand a zfs raidz pool by adding a single device, this is a zfs limitation, not Unraid, Unraid allows you to expand a raidz pool by adding a new vdev with the same width, in this case you would need to add 3 new disks.

 

 

25 minutes ago, JorgeB said:

I'm sorry, I didn't read the 1st post correctly, you can only expand a zfs raidz pool by adding a new vdev of the same width, this is a zfs limitation, not Unraid, in this case you need to add 3 new disks.

 Thank you, that seems to be correct but hopefully will be changing. 🤞 This is released soon. https://github.com/openzfs/zfs/pull/15022

It should change in about a year, with openzfs 2.3.

On 2/7/2024 at 11:44 AM, JorgeB said:

It should change in about a year, with openzfs 2.3.

Change meaning the ability to add a single disk to a pool? I'm considering to move to zfs pool from the unraid array but don't want to if that functionality isn't there yet.

2 hours ago, downloadedskill said:

Change meaning the ability to add a single disk to a pool?

Yes, OpenZFS 2.3 was released yesterday, it should be included with Unraid 7.1

 

 

With the recent release of Unraid 7.1, is it now possible to expand a ZFS Raidz pool?

2 hours ago, skler said:

With the recent release of Unraid 7.1, is it now possible to expand a ZFS Raidz pool?

Yep, but using the CLI only for now:

https://forums.unraid.net/topic/46802-faq-for-unraid-v6/page/4/#findComment-1537164

 

I'm doing it, and seems to work
 

# zpool status zfs
pool: zfs
state: ONLINE
expand: expansion of raidz1-0 in progress since Fri Mar 28 16:58:13 2025
    63.5G / 39.6T copied at 349M/s, 0.16% done, 1 days 09:00:19 to go

 

But the GUI is not aligned. It will be fixed to the next array start or I have to wait a system update? 

 

 

Edited March 28, 20251 yr by skler

4 minutes ago, skler said:

But the GUI is not aligned

See the FAQ entry, you need to reimport the pool after.

Hi - I'm trying this process - adding a drive to a ZFS raidz pool.  Am getting the following error...

cannot attach /dev/sdf1 to raidz1-0: can only attach to mirrors and top-level disks

 

This was a clean build on Unraid 7.0.1 just after release.

 

I thought this error was due to the previous ZFS 2.3 in ability to expand raidz and it was fixed as per the guide you linked in this thread. Am I doing something wrong?

homehub-diagnostics-20250331-1810.zip

Ignore me - unraid 7.1 and I'm on 7.0.1 

 

Will upgrade and try again

 

28 minutes ago, tfm said:

Will upgrade and try again

Yep, it won't work with 7.0

On 3/28/2025 at 5:06 PM, JorgeB said:

See the FAQ entry, you need to reimport the pool after.

Sorry Jorge if I bother you bat can you confirm that "remove pool" doesn't remove the pool (with all my data) from zfs but is something related only to the gui?

 

Ref: Step "on main, click on the first device for that pool and then "remove pool"" from https://forums.unraid.net/topic/46802-faq-for-unraid-v6/page/3/#findComment-1537164

One more thing, to move files from the an array disk to this new pool is safe to use unbalanced with -H for hardlink support? 

 

 

 

1 hour ago, skler said:

can you confirm that "remove pool" doesn't remove the pool (with all my data) from zfs but is something related only to the gui?

"Remove pool" doesn't touch the pool data, it only removes the pool from the GUI, "Erase pool" on the other hand will wipe the pool data.

 

1 hour ago, skler said:

to move files from the an array disk to this new pool is safe to use unbalanced with -H for hardlink support? 

I would recommend using the mover, it supports hardlinks.

24 minutes ago, JorgeB said:

"Remove pool" doesn't touch the pool data, it only removes the pool from the GUI, "Erase pool" on the other hand will wipe the pool data.

 

I would recommend using the mover, it supports hardlinks.

uhm maybe I'm missing something, the mover can move data from one disk of the array to a zfs pool (not included into the array)?

 

I'm quite sure is possible to do it with your unbalancer gui but with the mover I can only empty a disk moving data to the other array disks, or from cache to array etc 

5 minutes ago, skler said:

the mover can move data from one disk of the array to a zfs pool (not included into the array)?

Yes, set the pool as primary, array as secondary, movers action array > pool.