Summary
Highlights
Hard drives store vital information, but as physical devices, they are prone to failure. RAID (Redundant Array of Independent Disks) allows combining multiple drives for redundancy, ensuring data availability even if a drive fails. It's crucial to remember that RAID is not a backup solution; a separate backup process is still essential.
RAID 0, or striping, uses at least two drives to split data across them. This significantly increases read/write speeds as parts of a file are written concurrently to different drives. However, RAID 0 offers zero redundancy; if even one drive fails, all data becomes inaccessible.
RAID 1, or mirroring, involves creating an exact duplicate of data on at least two drives. While this doubles the required storage space, it provides excellent redundancy. If one drive fails, the mirrored drive ensures all data remains accessible, allowing for continuous operation while the failed drive is replaced.
RAID 5 combines striping with a single-parity drive. Data is striped across multiple drives, and one drive stores parity information instead of data. This allows for more efficient storage than mirroring and enables data reconstruction if one drive fails. There can be a slight performance hit during recovery due to parity calculations.
RAID 6 is similar to RAID 5 but includes two parity blocks across two separate drives. This configuration provides even greater fault tolerance, allowing the array to remain operational even if two physical drives fail. However, it requires an additional physical drive for the extra parity data, without increasing storage capacity.
RAID 10, or RAID 1+0, combines RAID 0 (striping) and RAID 1 (mirroring). This configuration involves striping data across mirrored pairs of drives, requiring at least four drives. It offers high performance and excellent redundancy, allowing for the loss of multiple drives (one from each mirrored pair) without data loss.