Expanding Storage Pools in Hexos – Support for Drives of Different Sizes?

[bonecrusher]

Hi everyone,

I'm considering purchasing Hexos, but I want to clarify how storage pool expansion works, especially regarding drives of different sizes. Since Hexos is based on TrueNAS, and TrueNAS does not support adding drives of different sizes to an existing pool without significant limitations, I’m wondering if this restriction carries over to Hexos as well.

One of the features I appreciate in Unraid is the ability to add drives of varying capacities over time without losing storage efficiency. Does Hexos offer a similar approach, or does it follow the same vdev-based structure as TrueNAS, where expansion requires entire vdevs of matching drive sizes?

Any insights would be greatly appreciated!

Thanks!

[Mobius]

Yes hexos will have similar limitations. 

You cannot expand with smaller drives but you can expand with same size or larger drives. 

If you expand with a larger drives it'll be treated as the same size as the smallest drive.

[gingerling]

Hi if I replace each drive with a larger drive will the whole pool later reset to the larger size?

[gingerling]

Found the answer here: 

 yes that should work

[austinthetaco]

On 3/17/2025 at 4:24 AM, Mobius said:

Yes hexos will have similar limitations. 

You cannot expand with smaller drives but you can expand with same size or larger drives. 

If you expand with a larger drives it'll be treated as the same size as the smallest drive.

I just tried replacing a drive with a larger capacity drive and hexos says it wont allow me and i need a "suitable candidate". is there something special I have to add a 16tb drive to the pool of 12tb drives?

[Mobius]

2 hours ago, austinthetaco said:

I just tried replacing a drive with a larger capacity drive and hexos says it wont allow me and i need a "suitable candidate". is there something special I have to add a 16tb drive to the pool of 12tb drives?

at this time it will have to be done via the underlying truenas interface

[Moahawk]

Hi I'm quite new to this and I consider doing the very same thing with my Raid1 setup consisting of 2x 2TB drives swapping to 8TB ones, but since I'm quite new to this and this HexOS system is my first NAS experience, I'm hesitant to just pull them out one by one and try for the best, I would like get some reinsurance that I'm not about to loose my precious data, can somebody help me find out what are the proper steps of doing this or at least point me in the right direction?

I do know how to get to the TrueNAS UI... but that's pretty much it when it comes to that 😛

[Mobius]

8 hours ago, Moahawk said:

Hi I'm quite new to this and I consider doing the very same thing with my Raid1 setup consisting of 2x 2TB drives swapping to 8TB ones, but since I'm quite new to this and this HexOS system is my first NAS experience, I'm hesitant to just pull them out one by one and try for the best, I would like get some reinsurance that I'm not about to loose my precious data, can somebody help me find out what are the proper steps of doing this or at least point me in the right direction?

I do know how to get to the TrueNAS UI... but that's pretty much it when it comes to that 😛

since you are just replacing 2 drives, have you considered just plugging  your 2 2tb drives and 2 8tb drives at the same time, copying over your data then removing your 2tb drives?

[Moahawk]

8 hours ago, Mobius said:

since you are just replacing 2 drives, have you considered just plugging  your 2 2tb drives and 2 8tb drives at the same time, copying over your data then removing your 2tb drives?

Thing is that I built this system in an old gifted computer with a motherboard that only supports 4 drives as far as I know (one of which is the boot drive is on a SSD), so I created a pool with just 2 drives, I did consider maybe plugging one 8tb drive in as a third and then copy the files or something, but should I do this manually?
I don't really know how I should go about this, do I create a new pool then? wouldn't that erase my data on my previous pool? some people said to just plug out one of the 2tb drives and replace it and let it rebuild but will that resize to the larger capacity? also I wouldn't want take this risk without knowing for sure it will work 😅

In the Docs I read something about 'Expanding Drives' but my pool says this is not supported since I only have 2 drives and not 3... 😞

What do you suggest I should do? thanks for the replies so far, I really appreciate the help 🙂

(P.S. also read somewhere on the forum that it would be possible to solve with the TrueNAS UI backend but I wouldn't even know where to begin really)

[Mobius]

11 hours ago, Moahawk said:

some people said to just plug out one of the 2tb drives and replace it and let it rebuild but will that resize to the larger capacity?

i would do this. it will not resize to larger capacity until you replace all the drives in the pool. but as always backup any mission critical data.

11 hours ago, Moahawk said:

(P.S. also read somewhere on the forum that it would be possible to solve with the TrueNAS UI backend but I wouldn't even know where to begin really)

i personally am not aware of such method.