Convert Proxmox Installation from BTRFS Z0 to Z1

[Unturned8798]

I have a PVE node (8.2.2) that was configured to use BTRFS on a single SSD. This disk contains my Proxmox installation, VMs, and CTs. I have also configured a PBS to create backups of my VMs and CTs, but I would like to add some resiliency to my PVE node by adding another SSD installation drive. Is it possible to convert my single disk Z0 BTRFS deployment to a two disk BTRFS Z1 without needing to start all over from backups?

I've tried to research this as much as possible, but I wasn't able to find the answer to my exact question. I've seen information that suggests this might be possible if the filesystem was ZFS; I also understand that if it was EXT4 or similar this would not be possible, but my findings surrounding BTRFS are not conclusive.

Thank you in advance for any guidance you can provide!

 

[Unturned8798]

I have continued to research further and found it is possible to convert BTRFS Z0 to Z1 (source) via:

mount /dev/sdb1 /mnt
btrfs device add /dev/sdc1 /mnt
btrfs balance start -dconvert=raid1 -mconvert=raid1 /mnt

However, I am not sure how to configure Proxmox to respect this change. Per the Proxmox Docs, perhaps no change would be needed as both drives would have the same path created?

The installer automatically partitions the disks and creates an additional subvolume at /var/lib/pve/local-btrfs. In order to use that with the Proxmox VE tools, the installer creates the following configuration entry in /etc/pve/storage.cfg:

dir: local
        path /var/lib/vz
        content iso,vztmpl,backup
        disable

btrfs: local-btrfs
        path /var/lib/pve/local-btrfs
        content iso,vztmpl,backup,images,rootdir

It seems too easy to be true, and I would much appreciate any second opinion/interpretation.