RAID: Level 3

RAID 3 combines byte-level striping with a single dedicated parity disk to ensure redundancy. Data is divided into small units, which are spread across multiple disks, while the parity disk stores information necessary for reconstructing lost data in case of a failure. A parity bit tells whether the sum of the $1$ bits in some data is even or odd (e.g., the parity of $100101$ is $1$ = odd.)

Performance is excellent due to parallel access: since only one disk is used for parity, the remaining disks contribute fully to storage capacity, making RAID 3 more efficient than mirrored configurations like RAID 1.

This level is particularly suitable for applications requiring sequential data access, such as video or audio streaming, where write speed is less critical. However, the reliance on a single parity disk creates a potential point of failure, reducing its overall reliability compared to more advanced levels.

RAID 3 is rarely used today due to its limitations and the availability of more robust alternatives.