NAS pSEO Landing
Brand Focus · TrueNAS
Estimate usable TB, parity, and fault tolerance for TrueNAS NAS users using 8x 16TB in RAID 10.
Raw Capacity
128.00 TB
Usable Capacity
57.60 TB
Fault Tolerance
1 drive per mirror pair*
Efficiency
50.0%
Excellent random I/O and rebuild behavior; capacity is typically 50% of raw. This scenario applies a 10% filesystem reserve.
Run Interactive Calculator →| Mode | Usable | Tolerance | Efficiency |
|---|---|---|---|
| RAID 5 | 100.80 TB | 1 drive | 87.5% |
| RAID 6 | 86.40 TB | 2 drives | 75.0% |
| RAID 10 | 57.60 TB | 1 drive per mirror pair* | 50.0% |
| RAID-Z1 | 100.80 TB | 1 drive | 87.5% |
| RAID-Z2 | 86.40 TB | 2 drives | 75.0% |
TrueNAS and ZFS planners usually care about parity width, scrub cadence, and healthy operating headroom. Capacity is only one part of pool durability.
A virtual device group in ZFS; multiple vdevs form a storage pool.
Background integrity scan that verifies checksums and repairs parity mismatches.
ZFS feature set and planning topic for growing parity groups safely.
For TrueNAS users, this NAS planning scenario estimates 57.60 TB usable after a 10% reserve from 128.00 TB raw.
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 per mirror pair*. Real-world survivability depends on mirror placement, rebuild stress, and drive health.
It can be practical, but larger drives increase rebuild windows. Validate parity choice and backup policy before committing to the final layout.