Enter the sizes of your data drives (and parity drives, if you already own them). The calculator tells you how many parity drives you need and how big they must be, then generates the snapraid.conf and the MergerFS /etc/fstab line to pool the data drives.
Enter your data drive sizes to size the array./etc/snapraid.conf
Enter your data drive sizes to generate snapraid.conf./etc/fstab MergerFS pool line
Enter your data drive sizes to generate the fstab line.How the parity recommendation works
The parity counts follow the official SnapRAID FAQ guideline:
| Data drives | Parity drives |
|---|---|
| 2–4 | 1 |
| 5–14 | 2 |
| 15–21 | 3 |
| 22–28 | 4 |
| 29–35 | 5 |
| 36–42 | 6 |
Each parity drive protects against one simultaneous drive failure. The one hard rule: every parity drive must be at least as large as your largest data drive. If you’re buying drives, it’s common to buy one size up for parity so future data-drive upgrades don’t force a parity upgrade too.
Unlike traditional RAID, SnapRAID parity costs you no capacity on the data drives: usable space is simply the sum of your data drives, and each file lives whole on one disk.
Why parity mounts at /mnt/pool/parity, not /mnt/pool/disk
The generated fstab line pools every mount matching /mnt/pool/disk* into MergerFS. If a parity drive were mounted at /mnt/pool/disk4, the glob would swallow it into the pool and your media apps would happily fill the parity drive with files. Mounting parity under a different prefix (/mnt/pool/parity1) keeps it out of the pool by construction.
After you copy the config
- Partition, format, and mount each drive first (the mounts referenced in
snapraid.confand fstab must exist). - Run
snapraid syncto build parity, then schedule regular syncs and scrubs. - Reload mounts with
sudo systemctl daemon-reload && sudo mount -a.
Full walkthrough of installing SnapRAID, what parity and content files actually do, and the sync/scrub routine that keeps the array healthy.
Where the fstab line above comes from: what each mount option does, and how to add a cache drive tier later.