How do I back up everything properly?
The 3-2-1 rule, what most people's backup is actually missing, and how to check it works before you need it.
- Difficulty
- beginner
- Time
- 1 hr
- Read
- 2 min
Short answer
Three copies, on two kinds of storage, one of them off-site. Cloud sync on its own is not a backup — it faithfully copies your mistakes, so a deleted or encrypted file disappears from every device at once.
Most people believe they have a backup and have a sync. The difference matters at exactly the wrong moment: sync propagates deletion and corruption everywhere, whereas a backup keeps a version from before it happened.
Step by step
- Work out what actually matters.Photographs, documents, and anything you created. Applications and the operating system reinstall; your own files do not.
- Apply the 3-2-1 rule.Three copies of the data, on two different types of storage, with one copy off-site. It survives a hard drive failure, a burglary and a fire.
- Set up an automatic local backup.An external drive with the built-in tool — File History on Windows, Time Machine on Mac. Automatic, because a manual backup is one you will stop doing.
- Add an off-site copy.A cloud backup service, or a second drive kept somewhere else and swapped periodically. A drive next to the computer does not survive a fire or a theft.
- Understand that sync is not backup.Cloud storage that mirrors a folder copies deletions and encryption too. Useful, but it is not protection against mistakes or ransomware.
- Keep version history where you can.Good backup tools and most cloud services keep previous versions. It is what lets you go back to before the problem.
- Test a restore.The step everybody skips. Restore one file and confirm it opens. An untested backup is a hope, not a plan.
- Include your phone.Photographs are usually the least replaceable thing anyone owns and they mostly live on a phone. Confirm it is actually backing up, and that it has not silently stopped for lack of space.
Tips
- Put a reminder in the calendar to test a restore twice a year. It takes five minutes and it is the only thing that proves the setup works.
- Encrypt any backup drive you keep elsewhere. A lost drive is a data breach otherwise.
- Check the backup is running. Failed backups often stop silently for weeks — most tools show the last successful date somewhere.
Common mistakes
- Treating cloud sync as a backup — It mirrors changes, including deletion and ransomware encryption, to every device within minutes.
- Keeping the only backup drive next to the computer — Fire, flood and burglary take both. One copy needs to be somewhere else.
Questions people ask
Is cloud storage a backup?
Not by itself. It syncs, so a deleted or corrupted file propagates everywhere. Services with version history come closer, but a real backup keeps independent copies.
How often should I back up?
Automatically and continuously for anything that changes daily. The right answer is however much work you are willing to lose.