ZFS move root to new pool (and keep the old pool)

[Afox]

Hello,

I think about adding faster drives to my setup that currently consists of 4 harddrives in a RAIDZ-2 configuration. There will be no drives removed, just added. The goal would be to run Proxmox and some VMs on this faster pool.

My main question is now if I can make this transition without reinstalling Proxmox and If this is possible what would be the best practice to do this?

Thanks and best regards

 

[aaron]

So if I understand you correctly, you want to create a new ZFS pool with faster drives, but still want to use the current drives later on in another pool? Ideally you would like to avoid reinstalling Proxmox VE?

 

[Dunuin]

Also keep in mind that the PVE system disks don't need great speed. What's really important is to have fast storage for your VMs/LXCs.
So shouldn't be a problem to keep the raidz2 and just add another pool with faster disks just as a VM/LXC storage.

 

[Afox]

So if I understand you correctly, you want to create a new ZFS pool with faster drives, but still want to use the current drives later on in another pool? Ideally you would like to avoid reinstalling Proxmox VE?

Correct.

Also keep in mind that the PVE system disks don't need great speed.

Every time Proxmox gets a kernel update it takes ages to finish it. If possible I would like to move Proxmox to this new pool as well.


I was hoping that this procedure would be easier as the original pool remains.

 

[Dunuin]

I was hoping that this procedure would be easier as the original pool remains.

Maybe that's possible, but I would bet it's faster and more reliable to just install everything from scratch.
And not sure how problematic it can be to keep the old pool. You then would get two pools called "rpool".
So you might need to export that old pool and import it using another pool name.

 

[aaron]

Since it has been mentioned by other people here in the forum already, I have no problem promoting it. Have a look at this post in my personal blog.
The premise is slightly different, as I had to move my Proxmox VE install on to smaller disks, but the procedure should be valid for your use case.

Only the step with the partition creation can be simplified if the new disks are the same size or larger. You can just copy the partition table and regenerate the UUIDs for them on the new disks. Taken from the Proxmox VE admin guide (Changing a failed boot device):

# sgdisk <source device> -R <new device>
# sgdisk -G <new device>

Then either delete the old pool or rename it to something you want and delete the old datasets on it.

Ideally, you test the procedure in a VM before you do it on the real system by installing a virtual Proxmox VE with a similar disk layout (can be much smaller since you don't store a lot of data).

 

[Afox]

I read your blogpost prior to posting but found that it did not match my case since I was guessing that, as said, the procedure would be less complex but apparently is not.

As recommended by @Dunuin it is probably the best to just reinstall Proxmox. Thanks for your help.

 

[aaron]

It is doable, but not simple

Depending on your setup, a fresh installation with backing up and restoring the guests can be a lot simpler.