Which RAID level uses mirroring to provide data availability when a drive fails?

Which RAID level uses mirroring to provide data availability when a drive fails?

• A. RAID Level 0
• B. RAID Level 1
• C. RAID Level 3
• D. RAID Level 5

Answer: (B)

Mirroring duplicates data on separate disks so you have a ready copy if one disk fails. This arrangement lets the system keep operating and serving reads even when a drive goes offline, because the other copy remains intact. The RAID level that uses this approach is RAID 1, which writes the same data to two drives and can continue to function and rebuild from the surviving drive after a failure. This provides strong data availability at the cost of storage efficiency since you effectively store the same data twice. In contrast, RAID 0 strips data across disks with no redundancy, so a single drive failure results in data loss. RAID 3 uses a dedicated parity drive for recovery, not a mirrored copy. RAID 5 distributes parity across all drives and can tolerate one drive failure, but it does not rely on data mirroring.

Mirroring duplicates data on separate disks so you have a ready copy if one disk fails. This arrangement lets the system keep operating and serving reads even when a drive goes offline, because the other copy remains intact. The RAID level that uses this approach is RAID 1, which writes the same data to two drives and can continue to function and rebuild from the surviving drive after a failure. This provides strong data availability at the cost of storage efficiency since you effectively store the same data twice.

In contrast, RAID 0 strips data across disks with no redundancy, so a single drive failure results in data loss. RAID 3 uses a dedicated parity drive for recovery, not a mirrored copy. RAID 5 distributes parity across all drives and can tolerate one drive failure, but it does not rely on data mirroring.