Changing, adding and removing drives from existing pool

[involut]

Hi,

I am currently running a FreeNAS server with a single storage pool. I am not completely new to FreeNAS, but unexperienced enough to have the following questions.

The pool consists of 4 identical 4000GB Seagate IronWolf ST4000VN008 drives which run perfectly fine for the time being. Now, I am looking into putting this server in a smaller footprint case. This thought led me to questioning the procedure of changing, adding and removing drives from this pool. Specifically:

a) if one drive fails, do I have to put in the same identical drive to replace the broken one?
b) when adding a single bigger sized drive to the pool as a replacement, I am sure it won't increase the overall available storage. But what happens if I replace all smaller drives successively by bigger ones? Will the overall storage size increase once the last smaller drive is replaced?
c) if at any point I would like to increase the pool's available storage space, how do I have to proceed? What is a best practice?

Best,
Michael

 

[Nick2253]

(a) It does not have to be identical. It just can't be smaller than the drive it's replacing. For example, if a 4TB WD drive fails, you could use any 4TB+ drive to replace it, but you could not use a 3TB or smaller drive.

(b) Once you replace all drives in a vdev with larger drives, the vdev will automatically expand, and that space will be available to the pool. https://www.ixsystems.com/documentation/freenas/11.3-U5/storage.html#replacing-disks-to-grow-a-pool

(c) There are two ways to expand a pool: (1) replace (one at a time!) all the drives in a vdev with larger drives, or (2) add more vdevs.

 

[involut]

Hey Nick,

That is very helpful, thank you very much. I do have a follow-up question regarding the procedure of replacing drives. If I would like to swap drives intentionally and replace it by either same sized or larger ones, how would I proceed correctly?
Initially, I thought I could somehow disconnect drives from within FreeNAS instead of just ripping it out.

The reason why I am asking is because the system does not have any free SATA ports where I could just add an additional drive.

 

[JaimieV]

If you can connect it somehow - (a PCIe SATA card is very cheap, $12; a USB3 caddy is probably more expensive but would also work) - then you can bring it into the system and in the Pools/Cogwheel screen choose "replace" on the drive you want to swap out. This avoids the risks associated with pulling a drive then rebuilding.

The replacement process is detailed in the User Guide, by the way. It's a good User Guide, you should use it.