RAID Level Comparison

Compare RAID configurations side-by-side to find the best fit for your storage needs

Quick Reference

Level Min Drives Capacity Tolerance Read Write Best For
RAID 0 2 100% 0 drives ★★★★★ ★★★★★ Speed-critical, temporary data
RAID 1 2 50% 1 drive ★★★★☆ ★★★☆☆ 2-4 drives, critical data
RAID 5 3 67-87% 1 drive ★★★★☆ ★★★☆☆ General NAS, ≤8TB drives
RAID 6 4 50-83% 2 drives ★★★★☆ ★★☆☆☆ Large drives, mission-critical
RAID 10 4 50% 1 per pair ★★★★★ ★★★★☆ Databases, VMs, high I/O
RAID 50 6 67-83% 1 per group ★★★★★ ★★★★☆ Large arrays, performance
RAID 60 8 50-75% 2 per group ★★★★★ ★★★☆☆ Enterprise, maximum safety

Detailed Comparison

RAID 0

Usable Capacity: 100%
Failure Tolerance: 0 drives
Redundancy: None
Cost per TB: Lowest
Rebuild Time: N/A
Pros:
  • ✓ Maximum capacity
  • ✓ Best performance
  • ✓ Simple setup
Cons:
  • ✗ No redundancy
  • ✗ Any failure = data loss
  • ✗ High risk

RAID 1

Usable Capacity: 50%
Failure Tolerance: 1 drive
Redundancy: High
Cost per TB: Highest
Rebuild Time: Fast
Pros:
  • ✓ Simple and reliable
  • ✓ Fast rebuild
  • ✓ Good read speed
Cons:
  • ✗ 50% capacity loss
  • ✗ Expensive per TB
  • ✗ Write speed limited

RAID 5

Usable Capacity: 67-87%
Failure Tolerance: 1 drive
Redundancy: Medium
Cost per TB: Medium
Rebuild Time: Slow
Pros:
  • ✓ Good capacity
  • ✓ Balanced performance
  • ✓ Standard solution
Cons:
  • ✗ Write penalty
  • ✗ Risky with large drives
  • ✗ Slow rebuild

RAID 6

Usable Capacity: 50-83%
Failure Tolerance: 2 drives
Redundancy: Very High
Cost per TB: Medium-High
Rebuild Time: Very Slow
Pros:
  • ✓ Dual failure protection
  • ✓ Safe with large drives
  • ✓ Better URE protection
Cons:
  • ✗ Slower writes
  • ✗ Lower capacity vs RAID 5
  • ✗ Complex parity

RAID 10

Usable Capacity: 50%
Failure Tolerance: 1 per pair
Redundancy: High
Cost per TB: Highest
Rebuild Time: Fast
Pros:
  • ✓ Best performance
  • ✓ Fast rebuild
  • ✓ High reliability
Cons:
  • ✗ 50% capacity
  • ✗ Expensive
  • ✗ Needs even drives

RAID 50

Usable Capacity: 67-83%
Failure Tolerance: 1 per group
Redundancy: Medium
Cost per TB: Medium
Rebuild Time: Medium
Pros:
  • ✓ Better than RAID 5
  • ✓ Good for large arrays
  • ✓ Faster rebuild
Cons:
  • ✗ Complex setup
  • ✗ Needs 6+ drives
  • ✗ Multiple parity drives

RAID 60

Usable Capacity: 50-75%
Failure Tolerance: 2 per group
Redundancy: Very High
Cost per TB: High
Rebuild Time: Very Slow
Pros:
  • ✓ Maximum protection
  • ✓ Scalable
  • ✓ Multiple group tolerance
Cons:
  • ✗ Very complex
  • ✗ Expensive
  • ✗ Needs 8+ drives

Head-to-Head Comparisons

RAID 5 vs RAID 6

The Classic Dilemma

RAID 5

Capacity: 67-87%
Tolerance: 1 drive
Performance: Good
Cost/TB: Medium

RAID 6

Capacity: 50-83%
Tolerance: 2 drives
Performance: Good
Cost/TB: Medium-High

Verdict:

Use RAID 5 for drives ≤8TB in 3-6 drive arrays. Use RAID 6 for drives >8TB or mission-critical data. The extra parity in RAID 6 significantly reduces rebuild risk.

Example Scenarios:

4×4TB NAS: RAID 5 - Good capacity/safety balance
6×12TB NAS: RAID 6 - URE risk too high for RAID 5
8×8TB Media Server: RAID 6 - Safety during long rebuilds

RAID 10 vs RAID 6

Performance vs Capacity

RAID 10

Capacity: 50%
Tolerance: 1 per pair
Performance: Excellent
Cost/TB: Highest

RAID 6

Capacity: 50-83%
Tolerance: 2 drives
Performance: Good
Cost/TB: Medium-High

Verdict:

RAID 10 wins for performance (databases, VMs). RAID 6 wins for capacity and safety with large drives. Cost per TB is much better with RAID 6.

Example Scenarios:

Database Server: RAID 10 - Best I/O performance
File/Media Storage: RAID 6 - Better capacity efficiency
4-drive Critical System: RAID 10 - Fast rebuild, high reliability

RAID 1 vs RAID 5

Small Arrays

RAID 1

Capacity: 50%
Tolerance: 1 drive
Performance: Good
Cost/TB: Highest

RAID 5

Capacity: 67-87%
Tolerance: 1 drive
Performance: Good
Cost/TB: Medium

Verdict:

For 2 drives, RAID 1 only option. For 3-4 drives, RAID 5 offers better capacity. RAID 1 has faster rebuild and simpler management.

Example Scenarios:

2-bay NAS: RAID 1 - Only option for 2 drives
3×4TB Array: RAID 5 - 67% vs 50% capacity
Boot Drive Redundancy: RAID 1 - Simple, reliable

Decision Guide

Choose RAID 0 if:

  • Maximum speed is critical and data is backed up elsewhere
  • Temporary scratch space or cache storage
  • You understand the risk and have backups

Choose RAID 1 if:

  • You have only 2 drives
  • Simple redundancy for boot/OS drives
  • Critical data with limited capacity needs

Choose RAID 5 if:

  • 3-6 drives with capacity ≤8TB each
  • Balanced capacity/performance/redundancy needed
  • Read-heavy workloads (media storage, file server)

Choose RAID 6 if:

  • Drives larger than 8TB
  • Mission-critical data requiring high availability
  • You want protection during rebuild
  • 4+ drive arrays where safety is paramount

Choose RAID 10 if:

  • Database server or VM datastore
  • High I/O, transaction-heavy workloads
  • Performance is more important than capacity
  • You have even number of drives (4, 6, 8)

Choose RAID 50/60 if:

  • Large arrays (12-48 drives)
  • Enterprise storage requirements
  • Need performance better than single RAID 5/6
  • Complex setup is acceptable

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