I’ve got a RAIDZ1 with 3 4TB Drives, is it possible to swap one at a time to 12TB or is there a better way?

Totally possible and the route that probably 80-90% people go to. Another way (if you have enough room and spare slots, is to just make another pool with the new 3 drives, make another pool, and just ZFS send/receive from your old pool to the new pool. It would likely be much faster, but would requ…

It is possible, but the slightly better way is to add the new drive and then do the replacement with the old drive still in place (= no loss of redundancy). Note though, that raidz1 gets less secure as drives get larger. If you can front-load the cost of at least 4 drives, creating a new raidz2 poo…

I glanced at the Docs for the current Scale. I didn’t see an in place option. Does it vary from the two procedures listed? Do you think in place should be added to docs? Replacing Disks Provides disk replacement instructions that take a failed disk offline and replaces a disk in an …

You’re looking at procedures for (totally) failed drives, which is not the case here. Whenever possible, it is better NOT to offline or remove the drive to be replaced, but let ZFS do it after the replacement. So, yes, the docs could be improved.

That document does mention online replacement… for a failing disk But I do think it over-emphasizes removing a disk and reducing redundancy. There should be a section on “Replacing healthy disks” which makes clear that online replacement is not only a viable option, but a safer option

I just put in Feedback for that section to add and pointed to this thread as an example

I would use the second method, but is it possible to tell the apps that they should use the new pool with the moved date. Is it as easy as going to the Apps tab and clicking the Choose pool under Configuration?

[image] SmallBarky: I glanced at the Docs for the current Scale. I didn’t see an in place option. Does it vary from the two procedures listed? Do you think in place should be added to docs? Replacing Disks | TrueNAS Documentation Hub Yes, it should be added: [image] […

I don’t know if that belongs in the Feature Request section. Document updates can be requested on the Document pages itself. On the right side of the documents pages is a Feedback tab. (as long as you haven’t blocked it with EFF Privacy Badger plugin in Firefox, ha ha) I already gave Feedback to …

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TrueNAS General

tangofan February 3, 2025, 9:19pm 10

Yes, it should be added:

Topic		Replies	Views
[Not Accepted] Documentation "feature" request for page TrueNAS Tutorials/Storage/Disks/Replacing Disks Feature Requests SCALE	4	89	October 9, 2025
Adding unassigned disk to a pool TrueNAS General SCALE	17	134	July 7, 2026
Correct way to increase the capacity of an existing pool TrueNAS General	29	6616	March 26, 2026
Upgrading Disks Question TrueNAS General Goldeye	17	215	May 26, 2026
Is pool auto-expansion just broken by design now? TrueNAS General ZFS	36	724	March 20, 2026

Expanding RAIDZ1

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