Best fit
RAID-Z1
Smaller ZFS pools where one-drive tolerance and capacity efficiency match the stated risk boundary.
- • Single parity.
- • Vdev shape affects future growth.
- • Snapshots do not create an independent backup.
ZFS choice
RAID-Z1 or RAID-Z2?
Choose a ZFS vdev layout by capacity, fault tolerance, future pool design, and the backup plan outside the pool.
Best fit
RAID-Z2
Users accepting the capacity cost of two-drive tolerance for a more conservative pool baseline.
- • Dual parity uses more raw capacity.
- • Needs enough bays to be a useful fit.
- • Pool design should be decided before the drive purchase.
Decision rule
Decide the vdev shape before buying drives. Compare both layouts against data importance, recovery copies, planned bay count, and how the pool will grow.
Build the baseline firstSources and scope
Last reviewed 2026-07-13. This page separates the decision it supports from the facts that still require a platform or model-specific check.
Applies to
ZFS vdev capacity and protection planning.
Does not coverA complete TrueNAS deployment design.