It's a hard pill to swallow, adding two more drives in a vdev to get one more drive worth of storage (authors case maxes out at 6 drives, currently has 4). So

It's a hard pill to swallow, adding two more drives in a vdev to get one more drive worth of storage (authors case maxes out at 6 drives, currently has 4). So often you will bite the bullet and just completely rebuild. True RAIDz expansion is something that's supposed to be coming, possibly in Q3 2022, so it may be that by the time one needs to expand a volume, that ability will have landed. That'll be a game changer.