Help making ZFS hd smaller

ℹ️ Support
#1

Hi all,

I’m new to Linux and very new to ZFS.

I’m trying to make a ZFS pool smaller. I’ve been trying to blunder may way through this for a couple of weeks and getting nowhere: time to ask for help from people who know what they’re doing.

Here’s the story: I am running Daniel Hansson’s excellent 40gb VM on VirtualBox on Windows 10. I keep almost no user files on the VM drives - they’re all on external storages.

But through some misdventures with preview generation, I filled up the the 40gb VM drives.

Following the nice little tutorial here (https://www.pandatech.co/2018/05/increase-nextcloud-13-storage-extend-zfs/), I added a new fixed 200gb VM drive to my ncdata zfs pool and all was good.

But now that I’ve got my previews figured out, I have WAY more space than I need.

For the sake of making quick clones of the VM, I’d like to replace the 200gb drive with a 10gb drive.

I won’t bore you with the things I’ve tried, but none have worked. I suspect I need to destroy the ncdata pool and recreate it with a smaller drive, but am not sure how to do that (or even if that’s right).

Hoping somebody with some ZFS skills can walk me through the best approach.

Thanks!

#2

There is no way to shrink a ZFS pool/partition/filesystem - sorry
There seemed to be some rumors around about implementing ability to shrink, but most people use some hacks (edit definitions and redefine sizes) or a second disk (mirror and then copy/move back to a smaller volume), but - to my knowledge - there is no command to simply say “resize please”.

#3

Thanks.

So I guess my question is what’s the best alternative? From what I can gather, it’s making a copy of ncdata, sending it to a tz, destroying the pool and then creating a new pool called ncdata with the smaller drive and receiving the ncdata copy back into it.

About to try it, but curious if anybody knows a better approach I’m missing.