Use the matrix
Compare capacity and tolerance before opening a platform-specific decision page.
Reference matrix
Compare layouts with the assumptions held constant.
Each column uses equal-size drives and a 10% planning reserve. This is a transparent capacity model, not a substitute for platform-specific expansion, compatibility, or recovery checks.
| Layout | Fault tolerance | 4 × 8 TB | 6 × 12 TB | 8 × 16 TB | Planning note |
|---|---|---|---|---|---|
| Mirror | One drive in a two-drive pair | 7.2 TB25% before reserve | 10.8 TB17% before reserve | 14.4 TB13% before reserve | Simple redundancy with one data-drive equivalent. |
| RAID 5 | One drive | 21.6 TB75% before reserve | 54.0 TB83% before reserve | 100.8 TB88% before reserve | Single parity with higher capacity efficiency. |
| RAID 6 | Two drives | 14.4 TB50% before reserve | 43.2 TB67% before reserve | 86.4 TB75% before reserve | Dual parity with an additional capacity cost. |
| RAID 10 | One drive per mirror pair | 14.4 TB50% before reserve | 32.4 TB50% before reserve | 57.6 TB50% before reserve | Mirrored pairs with roughly half of raw capacity usable. |
| RAID-Z1 | One drive | 21.6 TB75% before reserve | 54.0 TB83% before reserve | 100.8 TB88% before reserve | Single-parity ZFS vdev planning model. |
| RAID-Z2 | Two drives | 14.4 TB50% before reserve | 43.2 TB67% before reserve | 86.4 TB75% before reserve | Dual-parity ZFS vdev planning model. |
Then verify
Check the actual NAS, controller, ZFS vdev, SHR, or Unraid expansion rules before buying drives.
Continue
Build a storage baseline →