Edit: I found some info on "Creating RAIDZ2 Degraded". I'll give it a try and report back.

First, I apologize if I use the wrong terminology here. I'm new to ZFS.

My current setup is RAID6 using a hardware RAID card, with disks being 8-8-8-8-10-10 TB.

Current data that I'd like to migrate WILL fit on a single 10TB drive.

I'd like to migrate the same hard drives to a Proxmox RAIDZ2 vdev.

I understand that I can't add drives to a VDEV, so I'd have to make it with all 6 disks from the start.

I'd like to use one of the 10TB drives to hold my data (the risk with this is acceptable to me), create the VDEV, transfer the data, and finally add that drive to the VDEV.

Is there a way to "spoof" the 6th disk when I create the VDEV?

Thanks!