RAID Comparison & Storage Architectural Tradeoffs
Redundant Array of Independent Disks (RAID) balances performance, capacity, and fault tolerance across multiple storage drives. Choosing the right RAID level depends on your workload requirements.
| Level | Min Disks | Capacity Formula | Fault Tolerance | Primary Use Case |
|---|---|---|---|---|
| RAID 0 | 2 | N × Size | 0 (None) | Scratch disks, temporary rendering, high-speed gaming cache. |
| RAID 1 | 2 | 1 × Size | N - 1 Disks | OS boot drives, mission-critical database logs. |
| RAID 5 | 3 | (N - 1) × Size | 1 Disk | General file storage, media servers, backup arrays. |
| RAID 6 | 4 | (N - 2) × Size | 2 Disks | High-capacity enterprise NAS (recommended for drives ≥ 8TB). |
| RAID 10 | 4 (Even) | (N / 2) × Size | 1 per mirror pair | High-write transactional databases (SQL, Postgres, virtualization). |
Why RAID 5 is Dangerous on Large Drives (≥ 8TB)
When an 8TB or 16TB hard drive fails in a RAID 5 array, rebuilding the replacement drive requires reading every single bit from the remaining disks. During this multi-day rebuild, the statistical probability of encountering an Unrecoverable Read Error (URE) on consumer SATA drives is significant. If an unrecoverable read occurs during a RAID 5 rebuild, the entire volume can be lost. For modern high-capacity disks, RAID 6 or RAID 10 is strongly recommended.
Remember: RAID is NOT a Backup
RAID protects solely against hardware drive failures—it offers zero protection against ransomware, accidental deletion, filesystem corruption, or fire/flood disaster. Always implement the 3-2-1 backup strategy: 3 copies of data, across 2 different media types, with 1 copy stored off-site.