The 3-2-1 Backup Rule
One copy isn't a backup — it's just a file. The 3-2-1 rule is the simplest framework that actually protects you against drive failure, ransomware, and accidental deletion.
What 3-2-1 means
- 3 copies of your data total (the original + two backups)
- On 2 different types of media (e.g., internal drive + external USB, or computer + cloud)
- With 1 of them off-site (so a fire, flood, or burglary doesn't take everything)
What to back up
Documents, photos, contacts, browser bookmarks, password manager export, anything you've made or collected that you can't re-download. You don't need to back up Windows or installed apps — you can reinstall those. Focus on the stuff that's irreplaceable.
A cheap home setup
- Original on your PC or laptop.
- Backup #1: external USB drive, plugged in once a week. Copy your files; eject. Two drives is even better — rotate them, with one always at a relative's house or a safe-deposit box.
- Backup #2: a cloud backup service like Backblaze ($9/month, unlimited data, runs automatically).
Total cost: about $9/month plus a $50-100 USB drive. Worth every cent the first time you accidentally delete your tax folder.
A small-business setup
- Original on workstation or server.
- Local backup: a NAS (network-attached storage) running daily backups with version history. Synology and QNAP make good ones.
- Off-site backup: a cloud service like Backblaze B2, Wasabi, or AWS S3 with versioning. Rotates automatically.
Test your backups
A backup you've never restored from is just hope. Every six months, restore one file from each backup. Confirm it actually came back intact. If a restore fails, you find out now — not the day your drive dies.
Ransomware caveat
If your computer gets ransomware, it can encrypt anything it can write to — including a USB drive that's still plugged in, or a network share that's mapped. Use backup tools with version history (so you can restore yesterday's clean version) and disconnect external drives between backups.