Understanding Different RAID Levels: RAID 0, 1, 5, 6, and 10 Explained

Here is an explanation of the common RAID levels 0, 1, 5, 6, and 10, highlighting their key features, advantages, and disadvantages:

RAID 0 (Striping)

• Requires a minimum of 2 disks.
• Data is split into blocks and striped across all disks, improving read/write performance significantly.
• No redundancy or fault tolerance; if one disk fails, all data is lost.
• Total storage capacity is the sum of all disks.
• Best suited for non-critical systems where speed is the priority.

RAID 1 (Mirroring)

• Requires a minimum of 2 disks.
• Data is duplicated (mirrored) exactly on two or more disks.
• Provides excellent fault tolerance; if one disk fails, data is still available on the other.
• Storage capacity is effectively halved because data is duplicated.
• Performance for reads can improve, but writes are slower due to duplication.

RAID 5 (Striping with Distributed Parity)

• Requires a minimum of 3 disks.
• Data and parity (error correction information) are striped across all disks.
• Can tolerate the failure of one disk without data loss.
• Provides a good balance of performance, storage efficiency, and fault tolerance.
• Write performance is slower than RAID 0 due to parity calculations.

RAID 6 (Striping with Double Distributed Parity)

• Requires a minimum of 4 disks.
• Similar to RAID 5 but with two sets of parity information.
• Can tolerate failure of two disks simultaneously.
• Offers higher fault tolerance than RAID 5 but with additional overhead on write performance.
• Suitable for critical systems requiring high availability.

RAID 10 (RAID 1+0, Mirroring + Striping)

• Requires a minimum of 4 disks.
• Combines RAID 1 and RAID 0 by first mirroring data and then striping across mirrored sets.
• Provides both high performance and fault tolerance.
• Can tolerate multiple disk failures as long as no mirrored pair is completely lost.
• More expensive in terms of storage efficiency since half the capacity is used for mirroring.

This summary should help you understand the trade-offs between speed, redundancy, and storage efficiency for each RAID level. RAID 0 maximizes speed but has no fault tolerance, RAID 1 focuses on redundancy, RAID 5 and 6 add parity-based fault tolerance with varying levels of protection, and RAID 10 combines mirroring and striping for both speed and redundancy.