Just did it to test on a couple of files, worked fine.

The least bad imo is making a two drive raidz1 then expanding it.

So the broken pool is kinda stupid and you shouldn’t do it, you will be running without parity the whole time but if you want to risk it it does work.

Or… If you have the drives and space, you can combine a bunch of smaller drives with mdadm (assuming Linux but freebsd has geom I think) and then use that as your third drive, then once everything is copied do a zpool replace. That way you keep full parity the whole time.

Edit: latest version of zfs supports raidz expansion. So you could create a 2 drive raidz1 then copy everything over then expand it. You will still be running your source disk without parity but at least the destination would be safe.

Ubuntu server w/ zfs on the main.

Have a little atom hp home server at my parents house that uses almost no power, that runs freebsd x86, zerotier one, and kopia. Free cloud backup 😁

They have a lot of users voting and viewing content though.

Don’t worry pretty soon Reddit will join us in being tiny.