RAID 10 Calculator
When performance and redundancy are equally important, RAID 10 is one of the most powerful storage configurations available. It combines the speed of striping with the protection of mirroring, making it ideal for databases, virtualization, and high-performance servers.
Our RAID 10 Calculator helps you instantly determine:
- Total number of mirror pairs
- Raw capacity
- Usable capacity
- Mirror overhead
- Storage efficiency
- Fault tolerance
- Performance scaling
- Total hardware cost
- Cost per usable TB
Whether you're building a business server, NAS, or enterprise storage system, this tool gives you complete visibility before you invest.
What Is RAID 10?
RAID 10 (also called RAID 1+0) combines:
- RAID 1 (Mirroring)
- RAID 0 (Striping)
It creates mirrored pairs of drives, then stripes data across those mirrors.
Minimum Requirements:
- At least 4 drives
- Must use an even number of drives
RAID 10 is widely used in environments that require:
- High performance
- High availability
- Strong redundancy
How RAID 10 Works
RAID 10 organizes drives into mirror pairs.
Example:
If you use 6 drives:
- 3 mirror pairs are created
- Data is striped across those 3 mirrors
This structure delivers:
- Fast read speeds (across all drives)
- Strong write performance
- Excellent fault tolerance
How to Use the RAID 10 Calculator
Using the calculator is simple.
Step 1: Enter Number of Drives
- Minimum: 4
- Must be even (4, 6, 8, 10, etc.)
Step 2: Enter Drive Capacity (TB)
Input the size of each drive in terabytes.
Step 3: Enter Cost Per Drive
Add the price of a single drive to calculate total cost and cost per TB.
Step 4: Click Calculate
The tool will instantly display:
- Total Drives
- Mirror Pairs
- Raw Capacity
- Usable Capacity
- Mirror Overhead
- Storage Efficiency
- Fault Tolerance
- Performance Scaling
- Total Cost
- Cost per Usable TB
RAID 10 Capacity Formula
RAID 10 always sacrifices 50% of total storage for mirroring.
Calculations:
- Mirror Pairs = Number of Drives ÷ 2
- Raw Capacity = Drives × Drive Capacity
- Usable Capacity = Raw Capacity ÷ 2
- Overhead = Raw − Usable
- Efficiency = 50%
This makes RAID 10 predictable and easy to calculate.
Example RAID 10 Calculation
Let’s look at a real-world scenario.
Configuration:
- 8 Drives
- 4 TB per drive
- $120 per drive
Raw Capacity:
8 × 4 = 32 TB
Usable Capacity:
32 ÷ 2 = 16 TB
Mirror Pairs:
8 ÷ 2 = 4 pairs
Overhead:
16 TB
Efficiency:
50%
Total Cost:
8 × $120 = $960
Cost per Usable TB:
$960 ÷ 16 = $60 per TB
This shows how RAID 10 trades efficiency for performance and reliability.
RAID 10 Performance Explained
RAID 10 offers excellent performance characteristics.
Read Performance:
- Can scale with total number of drives
- Multiple mirrors can serve read requests simultaneously
Write Performance:
- Scales with number of mirror pairs
Example:
- 8 drives = 8x read scaling
- 4 mirror pairs = 4x write scaling
This makes RAID 10 ideal for:
- Databases
- Virtual machines
- Transaction-heavy systems
- High IOPS environments
RAID 10 Fault Tolerance
RAID 10 can tolerate:
- One drive failure per mirror pair
Example:
With 4 mirror pairs (8 drives), you could potentially lose 4 drives — as long as no mirror loses both drives.
However:
If both drives in the same mirror pair fail, data is lost.
This makes RAID 10 significantly safer than RAID 5 in high-risk environments.
RAID 10 vs Other RAID Levels
RAID 0
- 100% efficiency
- No redundancy
RAID 1
- 50% efficiency
- Mirroring only
RAID 5
- Better efficiency
- Single drive fault tolerance
RAID 6
- Double parity
- Higher redundancy
RAID 10
- 50% efficiency
- Excellent performance
- Strong redundancy
For performance-critical systems, RAID 10 is often preferred over RAID 5 or RAID 6.
When Should You Choose RAID 10?
RAID 10 is best for:
- SQL databases
- Virtualization hosts
- Financial systems
- Email servers
- High-transaction workloads
It may not be ideal for:
- Budget storage
- Archive systems
- Backup repositories
Why Cost per TB Matters
RAID 10 sacrifices 50% of storage capacity.
This increases cost per usable TB compared to RAID 5 or RAID 6.
However, you gain:
- Faster rebuild times
- Better write performance
- Lower risk during rebuild
- Improved system stability
The RAID 10 Calculator helps you evaluate whether the performance benefits justify the cost.
RAID 10 Best Practices
- Always use identical drives.
- Monitor drive health regularly.
- Keep spare drives available.
- Combine RAID with proper backups.
- Avoid mixing drive types.
15 Frequently Asked Questions (FAQs)
1. What is the minimum number of drives for RAID 10?
Minimum 4 drives.
2. Why must RAID 10 use even drives?
Drives are paired into mirrors.
3. What is RAID 10 efficiency?
50%.
4. How is usable capacity calculated?
Total raw capacity divided by 2.
5. Is RAID 10 better than RAID 5?
For performance and reliability, yes.
6. Can RAID 10 survive multiple drive failures?
Yes, as long as no mirror pair loses both drives.
7. Is RAID 10 good for databases?
Yes, it’s highly recommended.
8. Does RAID 10 improve write performance?
Yes, better than RAID 5 in many cases.
9. What happens during rebuild?
Only the failed mirror rebuilds, reducing risk.
10. Is RAID 10 expensive?
It has higher cost per TB due to 50% efficiency.
11. What is mirror overhead?
The 50% of storage used for redundancy.
12. Does RAID 10 replace backups?
No. RAID is not a backup solution.
13. Can I expand RAID 10 later?
Depends on controller support.
14. Is RAID 10 safe for large drives?
Yes, rebuild risk is lower than RAID 5.
15. Is this RAID 10 calculator accurate?
Yes, it follows standard RAID 10 formulas.
Final Thoughts
The RAID 10 Calculator is a powerful planning tool for anyone building high-performance, fault-tolerant storage systems.
It provides instant insight into:
- Capacity
- Efficiency
- Mirror structure
- Performance scaling
- Cost analysis
Before purchasing drives or deploying a server, use this calculator to ensure your RAID 10 configuration meets both your performance and budget requirements.