Adding another 4TB disk to an existing 3 x 4TB disk pool to expand storage and keeping RAIDZ1

Vike

Dabbler
Joined
Apr 22, 2022
Messages
12
Hi all, first post here.

I am currently running a TrueNAS server with 3 x 4TB WD Red Plus disks in a RAIDZ1 configuration so I have 7TB of storage with parity. I have bought and added another disk to my remaining SATA port and need advice as to how I go about adding that new disk to my pool so that I increase my storage but still retain the RAIDZ1 configuration.

I understand that I can't just add the 4th drive to the same vdev without first formatting the existing 3 disks then recreating the pool with the 4 disks from scratch. Is this the case or is there any way of adding the 4th disk without backing up/erasing the existing data first? I don't mind losing my existing data and starting afresh if this is the only way but can someone please talk me through how to do this?

Also is this the most efficient way of maximising my storage with the 4 x 4TB if I want to have a one disk failure tolerance. I'm guessing it's very rare for two such disks to fail together before I can replace the faulty one. Or have I got that completely wrong?

Many thanks.
 

LarsR

Guru
Joined
Oct 23, 2020
Messages
714
zpool expansion is not yet possible. your only choice is to backup your data, destroy the pool and recreate it with the 4th drive.
 

Nick2253

Wizard
Joined
Apr 21, 2014
Messages
1,633
At this point, there is no way to expand a RAIDZ1 vdev without destroying and rebuilding it. However, the feature will (hopefully) be coming to OpenZFS soon. Not sure the exact timing, but I've seen reports that it could be as soon as August of this year.

Depending on your situation, it may be best to wait, or you might want to bite the bullet and rebuild.

 

Vike

Dabbler
Joined
Apr 22, 2022
Messages
12
Thanks LarsR and Nick, that's what I thought but I can't find how to recreate the pool with the 4 disks. Any chance of a step-by-step, please?
 

NugentS

MVP
Joined
Apr 16, 2020
Messages
2,945
You have to destroy the pool first, and erase all the data. See export and some of the tickbox options

Then just recreate the pool as you would normally
 

Vike

Dabbler
Joined
Apr 22, 2022
Messages
12
Thanks guys
 
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