if poolIdx < len(z.serverPools) && setIdx < len(z.serverPools[poolIdx].sets) {
		return z.serverPools[poolIdx].sets[setIdx].getDisks(), nil
	}
	return nil, fmt.Errorf("Matching pool %s, set %s not found", humanize.Ordinal(poolIdx+1), humanize.Ordinal(setIdx+1))
}

// Return the count of disks in each pool
func (z *erasureServerPools) SetDriveCounts() []int {