AWS Solutions Architect Associate Practice Test

The correct answer is RAID 1. RAID 1 is designed for data redundancy through mirroring, which means that every piece of data written to one disk is simultaneously written to another. This ensures that if one disk fails, the other disk still retains the data. However, this mirroring process doubles the amount of I/O operations required during write operations since each individual write request has to be executed twice—once for each mirrored disk. In contrast to RAID 0, which does not provide any redundancy but offers increased performance through striping, or RAID 5, which distributes parity information across all drives to provide fault tolerance without the overhead of mirroring, RAID 1’s specific method of achieving redundancy results in this characteristic of doubling I/O operations during writes. RAID 1+0 (or RAID 10) combines the features of both RAID 1 and RAID 0, providing striping and mirroring. Although RAID 10 does also involve mirroring, thereby doubling writes, the original question focuses on the mirroring aspect specifically found in RAID 1.