RAID 1 - Mirroring RAID Level 1 is achieved through what is called disk mirroring, and is done to ensure data reliability or a high degree of fault tolerance. In a RAID Level 1 configuration, the RAID management software instructs the subsystem's controller to store data redundantly across a number of the drives (mirrored set) in the array. In other words, the same data is copied and stored on different disks, or mirrored, to ensure that should a drive fail the data is available somewhere else within the array.

RAID 0 - Striping RAID Level 0 is not redundant, hence does not truly fit the "RAID" acronym. In Level 0, data is split across drives, resulting in higher data throughput. Since no redundant information is stored, performance is very good, but the failure of any disk in the array results in all data loss. This level is commonly referred to as striping.