RAID Performance Calculator
Compare read and write performance across RAID levels. Understand write penalties, IOPS characteristics, and throughput expectations.
✓ Read/write speed by RAID level
✓ Write penalty explained
✓ Workload recommendations
Distributes parity across all drives. Survives one drive failure. Good balance of capacity and protection.
Usable Capacity
11.82 TB
75.0% storage efficiency
RAID level comparison
| Level | Min | Fault tolerance | Capacity formula |
|---|---|---|---|
| RAID 0 | 2 | None | N × Size |
| RAID 1 | 2 | N−1 drives | 1 × Size |
| RAID 5 | 3 | 1 drive | (N−1) × Size |
| RAID 6 | 4 | 2 drives | (N−2) × Size |
| RAID 10 | 4 | 1/mirror pair | (N÷2) × Size |
| RAID 50 | 6 | 1/sub-array | (N−2) × Size* |
| RAID 60 | 8 | 2/sub-array | (N−4) × Size* |
| JBOD | 1 | None | N × Size |
| SHR | 1 | 1 drive (SHR-1) | ≈(N−1) × Size |
* Assumes 2 sub-arrays. N = number of drives.
RAID Performance by Level
RAID level dramatically affects both throughput (MB/s for large files) and IOPS (operations per second for small random reads/writes). Understanding write penalties is key to choosing the right level for your workload.
Write Penalty by RAID Level
RAID 0: 1:1 (no penalty) — fastest writes
RAID 1: 2:1 (mirror write) — moderate penalty
RAID 5: 4:1 (read-modify-write) — significant penalty
RAID 6: 6:1 (dual parity) — highest penalty
RAID 10: 2:1 (mirror write) — best write performance among redundant levels
Best RAID Level by Workload
- Database (random R/W): RAID 10 — lowest write penalty + excellent random IOPS
- File server (sequential read): RAID 5/6 — good capacity + fast sequential reads
- Video editing (sequential R/W): RAID 0 or RAID 10 — throughput is king
- Web server (read-heavy): RAID 5 — reads scale with drive count, writes are rare
- Email/VM server: RAID 10 — mixed random I/O needs low write penalty
Estimated Throughput (4 × HDD, ~200 MB/s each)
RAID 0: ~800 MB/s read, ~800 MB/s write
RAID 5: ~600 MB/s read, ~200 MB/s write
RAID 6: ~400 MB/s read, ~150 MB/s write
RAID 10: ~400 MB/s read, ~400 MB/s write
💡 SSD vs HDD
The write penalty matters most for HDDs. With SSDs, random IOPS are so high that even RAID 5/6 write penalties are manageable. For SSD arrays, prioritize capacity efficiency (RAID 5/6) over write optimization (RAID 10).