3-2-1 backup for a home NAS
Keep 3 copies of key files, on 2 kinds of storage, with 1 copy offsite (away from home). For a home NAS that means: the NAS itself, a USB drive, plus a cloud copy or a drive at a friend's house.
Updated 2026-09-23 · Sources below
Set it up in 5 steps
- List what cannot be replaced. Photos, home videos, docs. Not films you can re-download. Size that pile. For most families the irreplaceable part is far smaller than the whole NAS, which makes every later step cheaper.
- Copy 1 lives on the NAS. Your RAID array (see RAID levels) guards against one dead drive. That is copy one, not the whole plan.
- Copy 2 goes on a USB drive. Plug it in weekly, copy, then unplug and shelve it. Unplugged matters: ransomware and power surges cannot reach a drive in a drawer. Set a phone reminder, because humans forget weekly chores.
- Copy 3 lives offsite. Two good options: cloud backup of just the irreplaceable pile, or a USB drive kept at a friend’s or family member’s house. Check current cloud prices per provider before you commit; we date every figure on this site.
- Test once a quarter. Pull one old photo back from each copy and open it. A backup you never test is a rumor. If a copy fails the test, fix it that week.
Pick your offsite
| Option | Cost shape | Good for | Catch |
|---|---|---|---|
| Drive swap with kin | Free after the drive | Anyone with a willing human nearby | You must actually swap it monthly |
| Cloud, essentials only | Small monthly fee per TB | Set-and-forget people | Backing up 10 TB of films gets pricey; stick to irreplaceable files |
| Second NAS at family | Hardware cost once | Big piles, fast restores | You maintain two boxes, not one |
What most people skip
Unplugged beats always-on. A USB drive that stays plugged in dies with the NAS in a surge and encrypts with it in ransomware. Copy, unplug, shelve. Boring works.
Encrypt the offsite copy. If a drive lives at someone else’s house, turn on the encryption option your system offers. Then the favor you ask is small: shelf space, not trust with your files.
Keep old versions for a while. A deleted file you notice a month later needs last month’s copy, not yesterday’s. Whatever tool you use, keep version history on, at least for docs and photos.
Quick answers
Is RAID enough? Do I still need backup?
You still need backup. RAID survives dead drives. It does not survive fire, theft, ransomware, or deletes. Say it with us: RAID is not backup.
How much cloud space do I need?
Only the irreplaceable pile: photos, videos, docs. Measure it (step 1 above). Most families land well under 2 TB, which is the cheapest tier of most providers.
Should the USB backup stay plugged in?
No. Copy, unplug, shelve. An always-plugged backup shares the NAS’s fate in surges and ransomware. The five seconds of unplugging buys real safety.
How often should backups run?
Weekly for files that change. Right after each import for photos. Test a restore once a quarter. Put all three on reminders or they will not happen.
Is swapping drives with family awkward?
Encrypt the drive and it is just shelf space. Say you each hold the other’s encrypted drive: both homes are safer for the price of dinner conversation.
Go deeper
- Backblaze: the 3-2-1 backup strategy — the classic explainer, with worked examples.
- TrueNAS documentation — replication tasks that copy datasets offsite on a schedule.
- Synology Knowledge Center — Hyper Backup guides for prebuilt boxes.
- RAID levels explained — what copy 1 does and does not protect.
- r/DataHoarder — backup drills and restore stories from people with big piles.
Bottom line: NAS plus USB plus offsite, then test. RAID guards one dead drive; only tested backup guards the rest.
Sources
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