Say you have `1, 1, 2, 2` sized devices. A raidz requires them all to be equally sized which can be done by first adding `1 + 1 = 2` and then creating a zpool with `[1+1], 2, 2`. Can this 1 + 1 step be done within zfs? Hypothetically this would be done by creating a raid0 pool and then a raidz on top via `zfs create tank raidz (raid0 a1 b1) c2 d2`, or first running `zfs create ab1 a1 ab` and use that in the next `zfs create ab1 raidz ab1 c2 d2`.