1. What is RAID?
RAID (Redundant Array of Independent Disks) is a technology that combines multiple physical hard drives into a single logical unit. This is done to improve data performance, increase storage capacity, and/or provide redundancy to protect against data loss in case of a drive failure.
2. What are the most common RAID levels and their key differences?
The most common RAID levels are:
RAID 0 (Striping): Offers the best performance and full storage capacity but provides no redundancy. A single drive failure results in total data loss. Minimum of 2 drives.
RAID 1 (Mirroring): Provides excellent data safety by duplicating data across drives. However, it has lower storage efficiency (50%) and does not improve write performance. Minimum of 2 drives.
RAID 5 (Striping with Distributed Parity): A popular balance of performance, capacity, and redundancy. It uses distributed parity to withstand a single drive failure. Storage efficiency is (N-1)/N. Minimum of 3 drives.
RAID 10 (Mirroring + Striping): Combines the performance of RAID 0 with the safety of RAID 1. It offers high data protection (can survive multiple drive losses in specific scenarios) and fast performance, but at a 50% storage cost. Minimum of 4 drives.
3. How do I choose the right RAID level?
The choice depends on your priorities:
Performance (Speed): Choose RAID 0 (for non-critical data) or RAID.
Data Safety/Redundancy: Choose RAID 1, RAID 5, RAID 6, or RAID 10.
Storage Efficiency/Cost: Choose RAID 5 or RAID 6 for a good balance of capacity and protection.
4. Is RAID a substitute for backups?
No. A common misconception is that RAID replaces backups. RAID protects against physical hardware failure of a drive. It does not protect against data deletion, corruption, viruses, software bugs, or catastrophic events like fire or flood. A comprehensive backup strategy is always essential.
5. What is a hot spare drive?
A hot spare is an extra, unused drive installed in a RAID system. If a active drive fails, the system automatically begins rebuilding the data onto the hot spare drive, restoring redundancy without immediate manual intervention.
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