Raid 15 Calculator
'/%3E%3Ccircle cx='48' cy='39' r='19' fill='%23f2c9a5'/%3E%3Cpath d='M27 35c3-16 39-17 42 2-8-8-27-9-42-2z' fill='%23374151'/%3E%3Cpath d='M21 86c5-24 49-28 56 0z' fill='%232563eb'/%3E%3Ccircle cx='41' cy='41' r='2' fill='%23111827'/%3E%3Ccircle cx='55' cy='41' r='2' fill='%23111827'/%3E%3Cpath d='M42 52c4 3 9 3 13 0' stroke='%2392400e' stroke-width='3' fill='none' stroke-linecap='round'/%3E%3C/svg%3E)
Reviewed by Calculator Editorial Team
RAID 15 combines the features of RAID 1 (mirroring) and RAID 5 (striping with parity). This calculator helps you determine the storage capacity, redundancy, and performance characteristics of a RAID 15 configuration.
What is RAID 15?
RAID 15 is a storage virtualization technology that combines data striping with distributed parity and mirroring. It provides excellent read performance, good write performance, and excellent fault tolerance.
Key characteristics of RAID 15:
- Uses both mirroring and parity for redundancy
- Requires at least 4 disks (minimum 2 mirrored pairs)
- Provides protection against multiple disk failures
- Offers good performance for both reads and writes
- Uses disk space more efficiently than RAID 10
RAID 15 is less common than RAID 10 or RAID 5 but offers unique benefits for certain applications requiring both high performance and high redundancy.
How to Use This Calculator
- Enter the number of disks in your RAID 15 configuration
- Select the capacity of each disk (in GB or TB)
- Choose the unit for the results (GB or TB)
- Click "Calculate" to see the results
- Review the calculated values and chart
The calculator will show you the total capacity, usable capacity, and redundancy information for your RAID 15 configuration.
RAID 15 Formula
Total Capacity: Number of disks × Disk capacity
Usable Capacity: (Number of disks - 2) × Disk capacity
Redundancy Level: 2 disks (mirrored pair)
RAID 15 uses two disks for redundancy (mirroring) and distributes parity across all disks. This provides protection against multiple disk failures while maintaining good performance.
Example Calculation
Let's calculate for a RAID 15 with 6 disks, each with 2TB capacity:
| Metric | Calculation | Result |
|---|---|---|
| Total Capacity | 6 × 2TB | 12TB |
| Usable Capacity | (6 - 2) × 2TB | 8TB |
| Redundancy | 2 mirrored disks | Can survive 2 disk failures |
This configuration provides 12TB of total storage with 8TB usable space, protected by mirroring on two disks.
FAQ
How many disks are needed for RAID 15?
RAID 15 requires at least 4 disks (minimum 2 mirrored pairs). More disks provide better performance and redundancy.
What's the difference between RAID 15 and RAID 10?
RAID 15 uses distributed parity with mirroring, while RAID 10 uses mirrored stripes without parity. RAID 15 is more space-efficient but RAID 10 offers better write performance.
Can RAID 15 survive multiple disk failures?
Yes, RAID 15 can survive multiple disk failures as long as they don't all belong to the same mirrored pair.
Is RAID 15 better than RAID 5 for performance?
RAID 15 typically offers better read performance than RAID 5 due to the mirrored components, but write performance may be slightly lower.