NAS pSEO Landing
Brand Focus · TrueNAS
Compare usable TB, parity, and failure tolerance between RAID-Z3 and RAID-Z2 for TrueNAS NAS users.
This page compares RAID-Z3 and RAID-Z2 on identical hardware assumptions to help homelab builders choose between capacity efficiency and fault tolerance.
| Drives | RAID-Z3 | RAID-Z2 | Delta |
|---|---|---|---|
| 4x 8TB | N/A | 14.40 TB | N/A |
| 6x 8TB | 21.60 TB | 28.80 TB | -7.20 TB |
| 8x 8TB | 36.00 TB | 43.20 TB | -7.20 TB |
| 10x 8TB | 50.40 TB | 57.60 TB | -7.20 TB |
| 12x 8TB | 64.80 TB | 72.00 TB | -7.20 TB |
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.
Yes. The comparison table applies a 10% reserve baseline to reflect realistic operating headroom in NAS and homelab environments.
The better option is the one that keeps acceptable usable capacity while preserving safety margins during future disk expansions.
For TrueNAS users, this NAS planning scenario compares both modes at fixed drive sizes so you can see usable capacity differences before buying disks.
Yes. Similar usable TB does not imply similar failure tolerance or rebuild exposure. Capacity and resiliency should be evaluated together.