RAID Calculator – Capacity, Redundancy, and Performance
Calculate RAID array capacity, fault tolerance, and read/write performance.
About This Calculator
Calculate RAID array capacity, fault tolerance, and read/write performance. Use the calculator above for instant results.
Worked Examples
- Usable: 12 TB | Tolerate 1 failure
- Read: ~600 MB/s | Write: ~150 MB/s
Answer: 12 TB / 1 drive tolerance
- Usable: 32 TB | Tolerate 2 failures
- Better for large drives (URE risk)
Answer: 32 TB / 2 drive tolerance
- Usable: 8 TB | Tolerate 1+ failures
- Read: ~400 MB/s | Write: ~400 MB/s — fastest writes
Answer: 8 TB / fastest writes
Who Uses This Calculator?
Plan RAID arrays.
Data center storage decisions.
NAS and SAN configuration.
Home server storage planning.
Common Mistakes to Avoid
❌ RAID ≠ backup
RAID protects against hardware failure. It does NOT protect against deletion, ransomware, or site disaster. Always have offsite backups.
❌ Rebuild time risk
Large drives take hours to days to rebuild. RAID 5 with 12TB+ drives risks a second failure during rebuild. Use RAID 6.
Frequently Asked Questions
Best RAID for different needs?
Performance: RAID 0. Redundancy on budget: RAID 1. Balanced capacity+safety: RAID 5 or 6. Best performance+redundancy: RAID 10.
RAID 5 vs RAID 6?
RAID 6 survives 2 drive failures. Recommended for arrays with drives >4TB due to high URE rate during rebuild.
RAID vs ZFS?
ZFS adds checksums, self-healing, and better rebuild safety. Preferred for enterprise NAS over hardware RAID.