Pool expand

[sfo]

I am stuck with expanding a pool, not sure if i am doing it correctly.
My current system is having 9x6TB Toshiba disks. a pool is created and usable space is around 42TB. I have two more free slots and purchased 2X6TB drives.

how can I expand the pool so that i can utilize the newly purchased 6TB drives.

 

[sretalla]

We would need to understand your pool layout so the output of zpool status -v would help most to make that clear

I imagine you probably have a RAIDZ1 or RAIDZ2 pool with a single VDEV, so you're probably not going to be happy with the answers that we will give you.

 

[sfo]

i have a RAIDZ2

 

[sfo]

ReadyNas-A[~]# zpool status -v
pool: Pool
state: ONLINE
scan: resilvered 3.57T in 20:06:17 with 0 errors on Wed Jun 23 00:20:45 2021
config:

NAME STATE READ WRITE CKS UM
Pool ONLINE 0 0 0
raidz2-0 ONLINE 0 0 0
gptid/fabf37bf-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/faa20253-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/01e19fef-d34b-11eb-8787-e8fcafe7ad66 ONLINE 0 0 0
gptid/faf29f0d-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/fb403a1d-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/fb2e14bf-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/fb8e5a60-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/fbbd00c9-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0
gptid/fbe0fe6c-a5b3-11eb-98dc-e8fcafe7ad66 ONLINE 0 0 0

errors: No known data errors

pool: freenas-boot
state: ONLINE
status: Some supported features are not enabled on the pool. The pool can
still be used, but some features are unavailable.
action: Enable all features using 'zpool upgrade'. Once this is done,
the pool may no longer be accessible by software that does not support
the features. See zpool-features(5) for details.
scan: scrub repaired 0B in 00:00:33 with 0 errors on Sat Jul 3 03:45:33 2021
config:

NAME STATE READ WRITE CKSUM
freenas-boot ONLINE 0 0 0
ada3p2 ONLINE 0 0 0

errors: No known data errors

 

[sretalla]

OK, so as I suspected we're dealing with a pool that has a single RAIDZ2 VDEV.

That's probably not good news for you (although part of that news needs to be that you didn't do your research before using a filesystem that's obviously new to you). Read the ZFS primer: https://www.truenas.com/community/resources/introduction-to-zfs.111/

A RAIDZ (in your case RAIDZ2) VDEV can't (yet) be expanded by adding one or more disks to it.

The options you have to expand your pool are these:

1. copy all the data somewhere else, destroy the pool, recreate the pool with the additional disks included, restore the data back.

2. Add a second VDEV to the pool... (this is a little more elastic, but has complications)
Technically, you can add a VDEV of just one disk (but this is VERY BAD, because loss of any VDEV in the pool will destroy the pool, so don't do that)
So it makes sense that if you cared enough about your data to create a RAIDZ2 VDEV/pool in the first place, you would want that same level of protection, so you need to add a RAIDZ2 VDEV as the second one... minimum 4 disks to do that.
But for reasons of performance, you probably want to keep all of your VDEVs the same size (or at least the same width... number of disks), so you should really add another 9 disks if you're going to do that.

3. Wait for an unknown period of time (likely to be measured in months, but I suspect 18 months is probably the best case) until the RAIDZ expansion feature comes out of testing and is delivered into the mainstream OpenZFS product, and subsequently included in a version of TrueNAS, then expand your VDEV (1 disk at a time).