Add drive to RAIDZ2 pool in TrueNAS SCALE

[milanmdev]

Hello everyone,

I would like to add another drive to my RAIDZ2 pool in TrueNAS SCALE. I currently have 4, 2TB drives in 1 RAIDZ2 pool and I am looking to add a fifth drive. I see the expand pool button at the bottom of the pool actions context menu, but I can't find a way to add a drive to the pool so it can be expanded.

Thanks,
Milan Mehra

 

[Nomad]

Adding disk to RAIDZ2 pool

I am running the latest version of TrueNAS Core and I have a single RAIDZ2 pool with 4x 6TB drives. I was doing some reading and it seems to me that adding another 6TB drive or two to this pool to make a 6x 6TB RAIDZ2 pool is currently impossible (without rebuilding the pool from scratch). Is...

www.truenas.com

 

[danb35]

I would like to add another drive to my RAIDZ2 pool in TrueNAS SCALE

This is not possible in the way it sounds like you mean--you can't turn a four-disk RAIDZ2 into a five-disk RAIDZ2 without destroying and recreating the pool.

 

[NugentS]

Yet.

Sometime in the future you may be able to do so - perhaps, if the ZFS Gods & IX Goods are feeling generous. But not soon, probably

 

[milanmdev]

I see. Thanks for the responses.

 

[kelso]

So if I have 3 10TB drives in z1 configuration but have nothing on them yet as I am still learning how to set up.

AND if I were to add another 10 TB identical drive sometime down the line, would this just be a case of plugging it in and adding it to the existing setup?

 

[Whattteva]

So if I have 3 10TB drives in z1 configuration but have nothing on them yet as I am still learning how to set up.

AND if I were to add another 10 TB identical drive sometime down the line, would this just be a case of plugging it in and adding it to the existing setup?

Were you not reading the thread up to now?

This is not possible in the way it sounds like you mean--you can't turn a four-disk RAIDZ2 into a five-disk RAIDZ2 without destroying and recreating the pool.

Or to reiterate it in simpler terms. No, you cannot just add a free drive into any existing RAIDZn willy-nilly.

This is, however, perfectly doable and, perhaps, even encouraged in a mirror vdev provided the drive you're adding is either the same size or larger as the existing drives in capacity.

 

[kelso]

Were you not reading the thread up to now?


Or to reiterate it in simpler terms. No, you cannot just add a free drive into any existing RAIDZn willy-nilly.

This is, however, perfectly doable and, perhaps, even encouraged in a mirror vdev provided the drive you're adding is either the same size or larger as the existing drives in capacity.

I noted a new release on 13 December 2022 and thought that perhaps it would be possible.

Not everyone is smart on these forums. Me especially. Truenas adoption for me has been a seriously hard thing to do. I am trying to set up a network nas to have a single drive where I can store all my stuff plus go paperless.

The Changes in IT over the last decade has been huge. I read the Truenas docs and I get lost immediately. It will take a while for me to stop being a newbie because I have health issues and poor memory and like I said ain’t so smart as most others on this forum.

 

[Patrick M. Hausen]

Nobody is looking down on you. But to reiterate: modification of the topology (redundancy level. number of drives) of any RAIDZ vdev in ZFS is impossible. If this feature should become available any time in the future - and expect years, if at all - it will make the headlines not only on the forum, but Heise, Arstechnica, Serve the Home, about any IT news outlet you can think of.

It won't silently appear in a new release of TrueNAS.

HTH,
Patrick

 

[ChrisRJ]

I am trying to set up a network nas to have a single drive where I can store all my stuff plus go paperless.

If you are saying that you want to use a single drive only, i.e. have no redundancy, that is an extremely bad idea. In fact, a conventional non-ZFS file system will likely be more reliable in such a setup. The reason being that ZFS does not have a fsck (file system check) command. So if something goes only slightly wrong with a such a single drive, you probably lost data and have no chance to fix things.

 

[Arwen]

@ChrisRJ - That is not quite true. ZFS with redundant metadata and triple redundant critical metadata does mean if a block is lost in metadata, nothing is lost.

But, yes, you really have to accept that a ZFS striped pool could result in data loss. Or even entire pool loss.


My miniature media server uses striped disks for media. But, I have multiple, complete backups, so I can restore files, which I have done in the past. Or even the entire pool, which I hope I don't have to do. (I occasionally look for a new box to replace it as it is from 2015. But have not found anything I like yet.)

Weirdly enough, once when I lost a block, ZFS refused to tell me what file was impacted. In fact, their were no errors on a re-scrub. Took me weeks of thought to figure out I lost a block in metadata, which auto-corrected its self. Most of the prior errors were in video files, and largish ones at that, (because higher chance of a bad block in large files).

 

[Nomad]

I noted a new release on 13 December 2022 and thought that perhaps it would be possible.

Not everyone is smart on these forums. Me especially. Truenas adoption for me has been a seriously hard thing to do. I am trying to set up a network nas to have a single drive where I can store all my stuff plus go paperless.

The Changes in IT over the last decade has been huge. I read the Truenas docs and I get lost immediately. It will take a while for me to stop being a newbie because I have health issues and poor memory and like I said ain’t so smart as most others on this forum.

How much stuff are you looking to store? Many free tiers like OneDrive / Google drive offer a ton for just documents. I only use freenas for media storage and I'm even starting to move away from that. With 10TB at 1GBit streaming speeds for $100/yr it's hard to justify the cost anymore.

 

[WI_Hedgehog]

Hello everyone,

I would like to add another drive to my RAIDZ2 pool in TrueNAS SCALE. I currently have 4, 2TB drives in 1 RAIDZ2 pool and I am looking to add a fifth drive. I see the expand pool button at the bottom of the pool actions context menu, but I can't find a way to add a drive to the pool so it can be expanded.

Thanks,
Milan Mehra

Use LVM instead of ZFS. (as @danb35 will mention in the next post, that means do NOT use TrueNAS)

SAS drives, and I'd think all reasonable drives, use error recovery on the drive (hardware) to recover data in the event of an error. If data can't be recovered the drive reports an error and on a RAID-5 or RAID-6 system the data is read from a different drive.

ZFS takes this to the next level by adding more recovery information, however the functionality of slamming a drive into the RAID-n system and everything magically working is sacrificed, which is why it's not referred to as a RAID system, is a Z1, Z2, Z3 pool. TrueNAS is server-room server stuff, not desktop stuff or server-closet stuff, but rather data-center stuff. If a desktop-server and great backups do the job, use those; stepping up to data-center level "stuff" requires simplicity of thought, like "replace a server" verses "upgrade a system by adding a drive." (such is my thought, your mileage may vary)

 

[danb35]

Use LVM instead of ZFS.

IOW, don't use TrueNAS.

 

[kelso]

I have one more question. It has been said somewhere else that one should have two SSD drives with the Truenas scale OS on it. Is it crucial? Should that drive fail would I loose my data that is stored on 3 sea gate ironwolfs? Would I not just be able to replace the boot SSD and reinstall truenas, which would then see my old data?

 

[danb35]

Would I not just be able to replace the boot SSD and reinstall truenas, which would then see my old data?

Yes.

 

[ChrisRJ]

If you have encrypted data the key is on the boot drive. That might be something to consider.

 

[Whattteva]

I have one more question. It has been said somewhere else that one should have two SSD drives with the Truenas scale OS on it. Is it crucial? Should that drive fail would I loose my data that is stored on 3 sea gate ironwolfs? Would I not just be able to replace the boot SSD and reinstall truenas, which would then see my old data?

I really don't understand people that do that unless they're running some enterprise system that needs 99.99% uptime. The vast majority of home users just need it to serve Plex most of the time and simply don't need that and can afford an hour or 2 (max) downtime. As long as you have your config backed up, it's just a simple reinstall and config restore... something that takes like 30 mins at most for me. Heck, I don't even really bother to backup my config cause it's simple enough (no VM's or jails) that I can just simply recreate it from scratch. Takes a bit more (like 15 min more), but who cares really.

To answer your question, the boot drives don't have anything to do with the safety of your data pool (unless you have encryption). You can simply just reinstall it and reimport your pool (or restore your config).

 

[ChrisRJ]

As long as you have your config backed up, it's just a simple reinstall and config restore...

Well, given the price of an additional small SSD, that is exactly the reason why I have a my boot drive as a mirror. 30 USD/EUR vs. the risk of having forgotten to backup things ... Of course that is a "luxury" view. But given my virtual hourly rate, an addition SSD is a no-brainer for me. It may be different for others, of course.

 

[NugentS]

I use @joeschmuck 's script to email me a config file (and loads of other stuff) every day. I have multiple copies of the config file available to me (and not stored on the NAS in question)