NAS pSEO Landing
Brand Focus · Synology
Estimate usable capacity, fault tolerance, and efficiency for Synology NAS users using 4x 8TB in RAID 5.
Raw Capacity
32.00 TB
Usable Capacity
21.60 TB
Fault Tolerance
1 drive
Efficiency
75.0%
Balanced capacity and redundancy, but rebuild stress can be high on large disks. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 21.60 TB | 1 drive | 75.0% |
| RAID 6 | 14.40 TB | 2 drives | 50.0% |
| RAID 10 | 14.40 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 21.60 TB | 1 drive | 75.0% |
| RAID-Z2 | 14.40 TB | 2 drives | 50.0% |
Synology users usually optimize for predictable rebuild behavior and conservative free-space policies, especially when using large-capacity SHR/RAID pools for media and backup workloads.
Synology Hybrid RAID that improves flexibility when mixing drive sizes.
Point-in-time snapshots used for rollback and data protection policies.
Logical disk group where RAID layout is created before volumes are provisioned.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.
No. Use this page for pre-purchase sizing, then validate with workload benchmarks, SMART health policy, and a tested restore plan.
For long-lived NAS pools, resiliency first is usually safer. Capacity can be expanded later, while a risky parity choice can force migration sooner.
This setup can tolerate 1 drive. Real-world survivability depends on mirror placement, rebuild stress, and drive health.