RAID 10 combines mirroring (RAID 1) and striping (RAID 0). In a RAID 10 setup with four disks, data is mirrored across two pairs of disks, and those pairs are striped for performance. This results in improved performance and fault tolerance, but the total usable storage is 50% of the total raw storage, meaning four 2 TB disks provide 4 TB of usable space.