Adding Disk to RaidZ1

[ForMyDemons]

Hi,

i use

Version:
TrueNAS-13.0-U5.2

with 3x6tb drives in the pool, i reached 80%+ space usage and wanted to add another 6tb drive but i can't figure out how i should be able to.

if i want to add another vdev core tells me i need at least 3 disks...
"This type of VDEV requires at least 3 disks" "Caution: Adding data vdevs with different numbers of disks is not recommended. First vdev has 3 disks, new vdev has 1."

i just want to add more space

 

[Arwen]

At present, you can NOT add a column / disk to a RAID-Zx vDev. It is a limitation of ZFS.

Their are 2 ways to expand a pool:

• Replace all the disks in a vDev with larger ones. One at a time, waiting for re-silver to complete, before moving on to next disk. After all are replaced, the vDev will grow in size to what the new disks allow. (And pool size will grow...)
• Add another vDev to your pool, like the GUI prompted you.

ZFS is not the most flexible RAID scheme out their. Some pre-planning sometimes helps eliminate future problems. In this case, using 2 way Mirrored vDevs allows both growing a pool by 2 new disks. And being able to replace 2 disks to also grow a pool.


All that said, their is a project, MANY years away, to allow exactly what you asked for. It's not perfect, as it won't re-balance existing data to parity ratio. But, it is better than not doing it.

 

[ForMyDemons]

Damn, is there a better way if i setup my truenas core again to have the ability to just add disks while having some redundancy?

I always thought i can add disks and surely the parity has to be calculated new or something like that and it will be fine.

is that only with truenas core or has every storage system that pitfall? like truenas scale, netapp, etc

 

[HoneyBadger]

All that said, their is a project, MANY years away

iX is actually sponsoring the push to get RAIDZ expansion completed and committed, so there's reason to believe that we don't necessarily need the all-caps "MANY" any longer. ;)

See the linked comments from @Kris Moore below:

Are we any closer to vdev expansion?

The last estimate I saw was "some time in 2023". I've just hit 99% capacity on my setup, which was supposed to last me years longer than this. Parkinson's Law of Data and all that. So I'm...kind of screwed, at least for now, it would seem. Trying to figure out what options I have, if any...

www.truenas.com

Or follow the progress of the PR on GitHub:

raidz expansion feature by don-brady · Pull Request #15022 · openzfs/zfs

Motivation and Context This feature allows disks to be added one at a time to a RAID-Z group, expanding its capacity incrementally. This feature is especially useful for small pools (typically with...

github.com

 

[Patrick M. Hausen]

Every storage system with RAIZn. If you set up your vdevs as mirrored pairs you can always add another pair. I don't know what other systems that do not use ZFS do.

 

[ForMyDemons]

thank you very much for your help, even if its sad to hear

 

[jgreco]

thank you very much for your help, even if its sad to hear

Given the trend of software towards relatively crummy proprietary solutions, this limitation of ZFS is mostly just annoying but can be planned around in the design phase of your project. I'd rather have this minor limitation and the awesome feature set that ZFS offers in many other ways. RAIDZ expansion has been talked about for years but in the last year has made substantial forward progress. With iX interested in making it happen, I would expect that it is possible to have it done within maybe a year. Still, expect maybe an additional year of letting other people test their pools on it before you risk any irreplaceable data on it....

 

[Arwen]

iX is actually sponsoring the push to get RAIDZ expansion completed and committed, so there's reason to believe that we don't necessarily need the all-caps "MANY" any longer. ;)
...

Yes, that probably was a bit harsh. I did forget that iXsystems was pushing this feature forward.

My only excuse is that this was first announced as possible in 2017:

OpenZFS Developer Summit 2017 - OpenZFS

openzfs.org

 

[jgreco]

My only excuse is that this was first announced as possible in 2017:

OpenZFS Developer Summit 2017 - OpenZFS

openzfs.org

So in other words we're likely to see it before we see large scale deployment of AT&T Fiber.

 

[Ericloewe]

Lofty goals for a company that can't get rid of lead-sheathed cable.