How do RAID 0, 1, and 5 differ in their performance and reliability?
The correct answer and explanation is:
Correct Answer:
RAID 0 offers the highest performance but no reliability. RAID 1 provides high reliability with moderate performance. RAID 5 balances performance and reliability using parity.
Explanation (300 words):
RAID stands for Redundant Array of Independent Disks. It is a method used to combine multiple physical drives into one logical unit to improve performance, reliability, or both. RAID 0, RAID 1, and RAID 5 are three commonly used configurations, each with different characteristics.
RAID 0, also known as striping, divides data into blocks and spreads them across two or more drives. This significantly improves read and write speeds because operations can be performed in parallel. However, RAID 0 provides no data redundancy. If even one disk fails, all data is lost. Therefore, it is ideal only in situations where performance is the sole priority and data can be restored from other sources.
RAID 1, also called mirroring, copies identical data onto two or more drives. This setup provides excellent data reliability because if one drive fails, the data remains available on the other drive. However, it does not offer significant performance gains in write operations since data must be written to multiple disks. Read performance can improve slightly because the system can read from either drive.
RAID 5 uses striping with distributed parity. It requires at least three drives. Data and parity information are spread across all drives, allowing the system to recover data in case one drive fails. It offers a good balance between performance and reliability. Read speeds are generally good, but write speeds are slower than RAID 0 due to the overhead of calculating and writing parity information. If a single drive fails, the array can continue to operate while the failed disk is replaced and rebuilt.
In summary, RAID 0 favors speed with no fault tolerance, RAID 1 emphasizes redundancy, and RAID 5 aims to deliver both performance and reliability with some compromise.