This level is implemented as a striped array whose segments are mirrored as RAID 1 arrays. RAID 1+0, get it? RAID 10 shares the same fault tolerance as RAID 1 (mirror), but gives fault tolerance with a striping mechanism that can yield very high read rates. Functionally, the array can perform read transactions on par with the lightning fast RAID 1 array, but the added fault tolerance comes at the price of additional data mirroring. As you can see, this solution is not easily scalable. Still, it could be a viable solution for a scenario in which RAID 1 is desirable, but additional performance is needed as well.