What type of backup system provides redundancy through mirroring?

The correct answer is the type of backup system that provides redundancy through mirroring, which is RAID 1.

RAID 1 works by duplicating the same data onto two or more hard drives. This means that if one drive fails, the data remains accessible from the other drive(s), as they contain an exact copy of the data. This mirroring process not only ensures data redundancy but also improves data availability and safety, making it an essential strategy for protecting critical information.

In contrast, RAID 0 does not provide redundancy; it focuses on striping data across multiple drives to enhance performance, but if one drive fails, all data is lost. RAID 5 includes parity for redundancy, protecting against a single drive failure, but it does not mirror data, rather it spreads data and parity across different disks. Striping can improve performance but does not inherently offer redundancy unless combined with other RAID levels.

RAID 1 is preferred when the key requirement is data redundancy as it allows immediate recovery without the risk of data loss due to drive failure.