Ultimate RAID Calculator: Compare Levels, Capacity & Performance

Your complete guide to RAID arrays with interactive calculations for every configuration

Table of Contents

1. What is a RAID Array?
2. RAID 0 – Striping (RAID 0 Calculator)
3. RAID 1 – Mirroring (RAID 1 Calculator)
4. What is RAID 5? – Parity (RAID 5 Calculator)
5. RAID 6 – Double Parity (RAID 6 Calculator)
6. RAID 1E – Striping and Mirroring (RAID 1E Calculator)
7. RAID 10, 50 & 60 – Nested RAID Levels
8. RAID 5E & 5EE – Enhanced Parity
9. Which RAID Level Should I Choose?
10. How to Use This RAID Calculator
11. Worked Example: RAID 6 vs. RAID 10
12. Frequently Asked Questions

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What is a RAID Array?

RAID (Redundant Array of Independent Disks) is a data storage technology that combines multiple physical disk drives into a single logical unit for the purposes of data redundancy, performance improvement, or both. Originally developed in 1987 at UC Berkeley, RAID has become the standard for server storage, NAS devices, and high-performance workstations.

Key Benefits of RAID:

• Data Protection: Automatic backup through mirroring or parity
• Increased Performance: Parallel data access across multiple drives
• Larger Logical Volumes: Combine small drives into large storage pools
• 24/7 Availability: Hot-swap capabilities for business continuity

According to Backblaze’s 2024 storage report, RAID-protected systems experience 95% less data loss compared to single-drive configurations, making RAID essential for business-critical data.

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RAID 0 – Striping (RAID 0 Calculator)

Best for: Maximum performance, non-critical data
Minimum drives: 2
Fault tolerance: None
Capacity efficiency: 100%

RAID 0, also known as “striping,” distributes data evenly across all drives in the array. Each file is split into blocks, with different blocks written to different drives simultaneously.

RAID 0 Performance Metrics:

• Read speed: 2-4× single drive speed
• Write speed: 2-4× single drive speed
• Use cases: Video editing scratch disks, gaming PCs, temporary storage

RAID 0 Calculator Formula:

Total Capacity = Drive Size × Number of Drives
Usable Capacity = 100% of total

Example calculation: 4× 2TB drives = 8TB total capacity

Risk factor: If ANY single drive fails, ALL data is lost. Backblaze statistics show RAID 0 arrays have a 46% higher failure rate than single drives due to multiple failure points.

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RAID 1 – Mirroring (RAID 1 Calculator)

Best for: Critical data, small servers
Minimum drives: 2
Fault tolerance: 1 drive failure
Capacity efficiency: 50%

RAID 1 creates exact copies (mirrors) of data on two or more drives. Every write operation duplicates data to all drives in the array.

RAID 1 Performance Metrics:

• Read speed: 2× single drive (can read from both drives)
• Write speed: 1× single drive (must write to all drives)
• Use cases: Boot drives, accounting systems, small business servers

RAID 1 Calculator Formula:

Total Capacity = Drive Size × Number of Drives
Usable Capacity = Single Drive Size
Overhead = (Number of Drives - 1) × Drive Size

Example calculation: 2× 4TB drives = 4TB usable, 4TB overhead

Real-world application: Small businesses using RAID 1 experience 99.9% uptime compared to 97.5% for single-drive systems (Dell Small Business Report, 2023).

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What is RAID 5? – Parity (RAID 5 Calculator)

Best for: Balanced performance and protection
Minimum drives: 3
Fault tolerance: 1 drive failure
Capacity efficiency: (N-1)/N

RAID 5 uses block-level striping with distributed parity. Parity information is spread across all drives rather than concentrated on a single drive.

RAID 5 Key Features:

• Parity distribution: Prevents bottleneck on single drive
• Read performance: Excellent (N-1 drives reading simultaneously)
• Write performance: Good, but requires parity calculation
• Rebuild time: Slow for large drives (critical vulnerability)

RAID 5 Calculator Formula:

Total Capacity = Drive Size × Number of Drives
Usable Capacity = Drive Size × (Number of Drives - 1)
Parity Overhead = 1 Drive Equivalent

Example calculation: 5× 3TB drives = 12TB usable (15TB total)

Industry insight: RAID 5 remains popular but faces challenges with modern large drives. A 2023 study showed 14TB drives have a 68-hour rebuild time in RAID 5, during which a second failure risks total data loss.

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RAID 6 – Double Parity (RAID 6 Calculator)

Best for: Large arrays, archival storage
Minimum drives: 4
Fault tolerance: 2 drive failures
Capacity efficiency: (N-2)/N

RAID 6 extends RAID 5 by adding a second parity block, providing protection against simultaneous failure of two drives.

RAID 6 Advantages:

• Enhanced protection: Survives two drive failures
• Large drive support: Safer for 8TB+ drives
• Long-term storage: Ideal for backup archives
• Write penalty: Higher than RAID 5 due to dual parity

RAID 6 Calculator Formula:

Total Capacity = Drive Size × Number of Drives
Usable Capacity = Drive Size × (Number of Drives - 2)
Parity Overhead = 2 Drive Equivalents

Example calculation: 8× 4TB drives = 24TB usable (32TB total)

Cost analysis: While RAID 6 has higher overhead (25% with 8 drives vs 12.5% for RAID 5), the protection against dual failures can save $15,000+ in data recovery costs for businesses.

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RAID 1E – Striping and Mirroring (RAID 1E Calculator)

Best for: Odd number of drives, enhanced mirroring
Minimum drives: 3
Fault tolerance: 1 drive failure
Capacity efficiency: 50%

RAID 1E (Enhanced RAID 1) combines mirroring and striping across an odd number of drives, offering better performance than traditional RAID 1.

RAID 1E Characteristics:

• Combined approach: Stripes data then mirrors stripes
• Odd drive support: Works with 3, 5, 7 drives
• Performance: Better than RAID 1, worse than RAID 0
• Capacity: Always 50% regardless of drive count

RAID 1E Calculator Formula:

Total Capacity = Drive Size × Number of Drives
Usable Capacity = Total Capacity ÷ 2
Overhead = Total Capacity ÷ 2

Example calculation: 3× 6TB drives = 9TB usable (18TB total)

Niche application: Primarily used in IBM servers and some SAN systems. Represents less than 3% of enterprise RAID deployments but offers unique advantages for specific configurations.

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RAID 10, 50 & 60 – Nested RAID Levels

RAID 10 (1+0): Mirroring then Striping

Minimum drives: 4
Fault tolerance: 1 drive per mirror set
Capacity efficiency: 50%

RAID 10 creates mirrored pairs, then stripes data across those pairs. Offers excellent performance and good redundancy.

Performance: Read 4×, Write 2× (with 4 drives)
Best for: Databases, virtualization, high-transaction systems

RAID 50 (5+0): RAID 5 Arrays Striped

Minimum drives: 6 (two RAID 5 sets of 3)
Fault tolerance: 1 drive per RAID 5 set
Capacity efficiency: Varies by configuration

Combines multiple RAID 5 arrays into a striped set. Better performance than single RAID 5, especially for large writes.

RAID 60 (6+0): RAID 6 Arrays Striped

Minimum drives: 8 (two RAID 6 sets of 4)
Fault tolerance: 2 drives per RAID 6 set
Capacity efficiency: Lower but maximum protection

Enterprise solution for massive storage requiring high performance and maximum fault tolerance.

Capacity calculation example (RAID 10):
4× 4TB drives = 8TB total, 4TB mirror pairs, 8TB striped = 8TB usable

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RAID 5E & 5EE – Enhanced Parity

RAID 5E (Enhanced)

Adds a hot spare that participates in parity calculations, improving performance over traditional RAID 5.

Features:

• Active hot spare: Included in stripe calculations
• Better performance: 15-20% improvement over RAID 5
• Same protection: Single drive failure tolerance
• Proprietary: IBM/LSI technology

RAID 5EE (Enhanced Enhanced)

Further improves on 5E with distributed hot spare and faster rebuild times.

Minimum drives: 4 (including integrated hot spare)
Capacity: (N-2)/N (similar to RAID 6 but different protection scheme)

Market position: These proprietary solutions represent about 8% of enterprise RAID deployments, primarily in IBM Power Systems.

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Which RAID Level Should I Choose?

Choosing the right RAID level depends on your specific needs. Here’s a decision matrix based on 2024 storage trends:

For Home Users:

• Media Storage/Backup: RAID 1 (2 drives) or RAID 5 (3+ drives)
• Gaming PC: RAID 0 (performance) or single SSD with cloud backup
• Home Server/NAS: RAID 5 or RAID 6 for balance of capacity and protection

For Small Businesses:

• File Server: RAID 6 (4+ drives) for data protection
• Database Server: RAID 10 for performance and redundancy
• Email Server: RAID 1 or RAID 5 depending on size

For Enterprises:

• Virtualization: RAID 10 for VM performance
• Backup Target: RAID 6 for capacity and dual protection
• High-Transaction: RAID 10 or SSD arrays
• Archival Storage: RAID 6 with large drives

Cost-Performance Analysis:

RAID Level	Cost/TB	Performance	Protection	Best Use Case
RAID 0	$20	★★★★★	☆☆☆☆☆	Temp files, caching
RAID 1	$40	★★★☆☆	★★★★★	Boot drives, critical data
RAID 5	$28	★★★★☆	★★★☆☆	General file servers
RAID 6	$33	★★★☆☆	★★★★★	Large arrays, backup
RAID 10	$40	★★★★★	★★★★☆	Databases, virtualization

Based on 4TB drives at $80 each, 2024 pricing

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How to Use This RAID Calculator

Our interactive RAID calculator simplifies complex storage planning. Here’s how to get the most accurate results:

Step-by-Step Guide:

1. Select Drive Capacity

• Choose between GB or TB units
• Use slider or input field (1-100TB range)
• Consider future growth: Add 25-30% to current needs

1. Set Number of Drives

• Minimum varies by RAID level (2 for RAID 0/1, 3 for RAID 5, etc.)
• Consider chassis/bay limitations
• Odd vs. even numbers matter for some RAID levels

1. Choose RAID Level

• Click visual buttons for RAID 0, 1, 5, 6, or 10
• Review automatic performance ratings
• Check fault tolerance indicators

1. Analyze Results

• Usable capacity (primary display)
• Overhead/wasted space
• Fault tolerance (drive failures survived)
• Performance characteristics

1. Compare Scenarios

• Use “Common Configs” for preset comparisons
• Adjust sliders to see real-time changes
• Note efficiency percentages

Pro Tips for Accurate Planning:

1. Account for Formatting: Actual usable space is 93-95% of calculated due to filesystem overhead
2. Consider Drive SMR/CMR: SMR drives reduce RAID 5/6 rebuild performance by 40%
3. Future Expansion: Some RAID levels allow expansion, others require complete rebuild
4. Hot Spares: Add 1-2 extra drives as hot spares for critical systems
5. Monitoring: Implement SMART monitoring regardless of RAID level

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Worked Example: RAID 6 vs. RAID 10

Let’s compare two common enterprise scenarios using 8× 8TB drives:

Scenario: 64TB Raw Storage Array

RAID 6 Configuration:

• Drives: 8 × 8TB = 64TB raw
• Usable: (8-2) × 8TB = 48TB (75% efficiency)
• Protection: 2 drive failures
• Write penalty: High (dual parity calculation)
• Rebuild time: ~72 hours for 8TB drive
• Cost: $6,400 (drives only)

RAID 10 Configuration:

• Drives: 8 × 8TB = 64TB raw
• Usable: 64TB ÷ 2 = 32TB (50% efficiency)
• Protection: 1 drive per mirror pair (up to 4, but specific)
• Write penalty: Low
• Rebuild time: ~8 hours for 8TB drive
• Cost: $6,400 (drives only)

Performance Comparison:

Metric	RAID 6	RAID 10	Winner
Sequential Read	600 MB/s	800 MB/s	RAID 10
Random Read (4K)	45,000 IOPS	75,000 IOPS	RAID 10
Sequential Write	250 MB/s	400 MB/s	RAID 10
Random Write (4K)	15,000 IOPS	40,000 IOPS	RAID 10
Rebuild Time	72 hours	8 hours	RAID 10
Capacity Efficiency	75%	50%	RAID 6
Protection During Rebuild	Vulnerable	Protected	RAID 10
Cost per Usable TB	$133	$200	RAID 6

Decision Factors:

Choose RAID 6 if:

• Maximizing capacity is primary concern
• Budget is constrained
• Workload is read-heavy (media streaming, archives)
• You can accept longer rebuild times

Choose RAID 10 if:

• Performance is critical (databases, virtualization)
• Write speed matters
• Fast rebuilds are essential for uptime
• Budget allows for lower efficiency

Real-World Recommendation: For a database server handling 10,000 transactions/minute, RAID 10’s performance advantage justifies the capacity penalty. For a backup target or media archive, RAID 6’s efficiency makes more financial sense.

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Frequently Asked Questions

Q1: Can I mix different size drives in RAID?

A: Technically yes, but it’s not recommended. Most RAID controllers will limit all drives to the smallest drive’s capacity. For example, 2TB + 4TB + 4TB in RAID 5 will only use 2TB from each drive = 4TB usable (with 6TB wasted).

Q2: How does RAID affect SSD lifespan?

A: RAID can increase write amplification on SSDs, potentially reducing lifespan by 15-25%. However, modern SSDs with wear leveling and over-provisioning mitigate this. RAID 5/6 with SSDs should use controllers with optimized parity algorithms.

Q3: What’s the maximum number of drives in a RAID array?

A: It varies by controller:

• Hardware RAID: Typically 16-256 drives
• Software RAID (Linux mdadm): Up to 28 drives per array
• ZFS: Effectively unlimited, but practical limits apply
• Windows Storage Spaces: 63 drives per pool

Q4: Can I convert between RAID levels without data loss?

A: Some conversions are possible with specific hardware/software:

• RAID 1 to RAID 5 (with additional drives)
• RAID 5 to RAID 6 (with additional drives)
• RAID 0 to RAID 1 (not typically supported)

Always backup before attempting conversions.

Q5: How much performance improvement does RAID 0 really give?

A: Theoretical maximum is N× single drive speed, but real-world gains are:

• 2 drives: 1.8-1.9× improvement
• 4 drives: 3.2-3.5× improvement
• 8 drives: 5-6× improvement (bottlenecked by controller)

Q6: What happens during RAID rebuild?

A: The array operates in degraded mode while:

1. New drive is identified
2. Parity data recalculates missing information
3. Data reconstructs on replacement drive
4. Array returns to normal operation

Performance drops 30-70% during rebuild.

Q7: Is RAID a backup solution?

A: NO. RAID protects against hardware failure but not against:

• Accidental deletion
• Malware/ransomware
• File corruption
• Natural disasters
• Theft

Follow the 3-2-1 backup rule: 3 copies, 2 different media, 1 offsite.

Q8: What’s better: Hardware RAID or Software RAID?

A: Depends on needs:

Hardware RAID:

• Pros: Better performance, battery-backed cache, OS independent
• Cons: Cost, vendor lock-in, proprietary

Software RAID:

• Pros: Lower cost, flexible, no hardware dependencies
• Cons: CPU overhead, boot drive vulnerability

For modern systems with multi-core CPUs, software RAID (especially ZFS, Btrfs) often outperforms budget hardware controllers.

Q9: How do I monitor RAID health?

A: Implement monitoring for:

• Drive SMART status
• Array degradation alerts
• Rebuild progress
• Performance metrics
• Temperature monitoring

Tools: mdadm (Linux), Storage Spaces (Windows), vendor-specific utilities.

Q10: What’s the future of RAID?

A: Emerging technologies include:

• Erasure coding: More efficient than parity (used in object storage)
• Distributed storage: Ceph, GlusterFS for scale-out architectures
• NVMe over Fabrics: Shared storage across networks
• Computational storage: Processing on the drive itself

However, traditional RAID will remain relevant for at least another decade due to its simplicity and widespread support.

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Key Takeaways for 2024 RAID Planning

1. RAID 5 is becoming risky with drives over 8TB due to long rebuild times
2. RAID 6 is the new standard for arrays with 4+ large drives
3. RAID 10 remains king for performance-critical applications
4. SSDs change the equation – consider endurance and over-provisioning
5. RAID is not backup – always maintain separate backup systems
6. Monitor proactively – most array failures are predictable with proper monitoring
7. Consider alternatives – ZFS, Storage Spaces, and Ceph offer modern features
8. Plan for growth – Storage needs typically double every 2-3 years

Final Recommendation: Use our RAID calculator to model different scenarios before purchasing hardware. Test performance with your actual workload when possible, and always have a tested recovery plan.

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Last Updated: March 2024 | Based on industry data from Backblaze, Dell, Seagate, and WD reliability reports. RAID calculations assume identical drives and optimal controller performance. Actual results may vary based on specific hardware, workload, and configuration.