I managed to get enough blank disks to migrate my server to ZFS pools (or at least try to)

I had 7x8TB drives, created the first pool of 4 drives, off to the races.

I added a single drive, expanded the pool. I "thought" it had finished adding the drive (I was mistaken) so I added another, and another.

Now I'm left with what I assume is asingle pool with 1 vdev of 5 drives, and 1 vdev of 2 drives. Unraid doesn't seem to acknowledge the second vdev for storage space though.

Just wondering how screwed am I, Do I have to add 3 more drives for the other vdev to be acknowledged/used?

 pool: mainzpool
 state: ONLINE
  scan: scrub repaired 1000K in 10:26:38 with 0 errors on Thu Oct 15 20:10:52 2026
expand: expanded raidz1-0 copied 20.5T in 2 days 03:15:39, on Thu Oct 15 09:44:14 2026
config:

	NAME           STATE     READ WRITE CKSUM
	mainzpool      ONLINE       0     0     0
	  raidz1-0     ONLINE       0     0     0
	    /dev/sda1  ONLINE       0     0     0
	    /dev/sdc1  ONLINE       0     0     0
	    /dev/sdk1  ONLINE       0     0     0
	    /dev/sdd1  ONLINE       0     0     0
	    /dev/sdb1  ONLINE       0     0     0
	  raidz1-1     ONLINE       0     0     0
	    /dev/sdj1  ONLINE       0     0     0
	    /dev/sdi1  ONLINE       0     0     0

errors: No known data errors

3 hours ago, mnovak said:

Do I have to add 3 more drives for the other vdev to be acknowledged/used?

Basically, yeah, Unraid doesn't support using vdevs with different widths. Also, it's not efficient to have a 2 device raidz1 vdev, since it will use 50% for parity. My recommendation would be to recreate the pool as a single vdev raidz2.

Well f*$@&

Really wish the documentation was clearer about expanding. Can't remove the drives once they're added, so I don't have enough spare space to clear off the drives to rebuild them into a single vdev.