Backups That Actually Restore
The one-sentence version: A backup you have never restored is a hope, not a backup. Make copies of the irreplaceable stuff, keep one copy somewhere else, and prove the copies work by restoring from them.
The 3-2-1 idea, in plain words
Forget the jargon; here's the shape of it:
- 3 copies of anything important (the original counts as one).
- 2 different places — e.g., your computer and an external drive. One fire, spill, or dead disk shouldn't take both.
- 1 copy somewhere else — a different building. Cloud storage counts. Your desk drawer doesn't.
That's it. Three copies, two places, one off-site.
Back up the irreplaceable, not everything
You don't need to back up your operating system or your apps — those reinstall. Back up what you can't re-download:
- Photos and home videos
- Documents (taxes, deeds, writing, schoolwork)
- Financial records, password-manager exports
- Configuration files you spent hours tuning (dotfiles, server configs)
Rule of thumb: if losing it would make you sad or cost you a weekend, it belongs in the backup.
Local vs. cloud
| External drive (local) | Cloud storage | |
|---|---|---|
| Speed | Fast restores | Depends on your upload speed |
| Cost | One-time purchase | Monthly/annual fee |
| Survives house fire | No | Yes |
| Survives you forgetting the password | Yes | No — don't lose the login |
| Privacy | Nobody else holds your data | The provider holds your data |
Use both if you can: local for fast restores, cloud for the off-site copy. That is 3-2-1 with one purchase and one subscription.
Versioning vs. mirroring — this distinction matters
- A mirror copies the current state. If you delete a file, the next mirror deletes the copy too. If a file gets corrupted, the corruption gets copied.
- Versioning keeps history: yesterday's version, last week's version. Delete something by accident and you can go back.
Prefer versioning. Most backup tools (Time Machine on Mac, File History on Windows, restic/borg on Linux, and most cloud backup services) keep versions by default. A plain folder-sync (Dropbox-style syncing, rsync without history) is a mirror — handy, but not a real backup on its own.
The restore test (do this part)
A backup is only proven when you restore from it. Twice a year, spend ten minutes:
- Pick one real file — a photo, a document.
- Rename the original (don't delete it yet).
- Restore that file from your backup.
- Open it. Compare: does it look right? Same size, same content?
- Put the original back.
Check: the restored file opens and matches the original. If it doesn't — wrong version, corrupted copy, backup job silently failing — you just found out on a calm Tuesday instead of during a crisis. Fix the backup, test again.
If your backup tool offers a "verify" feature, run it too, but it doesn't replace an actual restore.
The ransomware paragraph (one honest one)
Ransomware is malware that encrypts your files and demands payment for the key. Here's the honest version: a versioned, offline or off-site backup is the best defense an ordinary person has, because you can wipe the machine and restore instead of paying. But it is not magic — ransomware can also encrypt backups it can reach (a permanently-attached external drive, a synced cloud folder). That's why one copy should be disconnected or off-site, and why versioning matters: it lets you restore the version from before the encryption. Paying the ransom is not recommended — it funds the next attack and doesn't guarantee your files back. If it happens to you, see incident-response.md.
The habit
- List the irreplaceable stuff (ten minutes, once).
- Set up one local backup and one off-site backup.
- Make sure versioning is on, not just mirroring.
- Restore-test twice a year. Calendar it.
Next: home-network.md — the router and Wi-Fi standing between your stuff and the internet.