Backups in plain English: the 3-2-1 rule

Nearly every genuinely bad day I've been called into could have been a mildly annoying day instead, if there had been a backup. Not a complicated one. Any one.

The rule worth remembering is 3-2-1.

Three copies

The file you're working on counts as one. You need two more. If your only copy of the last decade of family photos is on the laptop, you have one copy, and one is the same as none.

Two different places

Two copies on the same computer aren't two copies — one dead drive takes both. Two different physical devices: the laptop and an external drive, or the laptop and a cloud account.

One off-site

This is the part people skip, and it's the part that matters when the problem isn't technical. A burglary, a burst pipe, or a fire takes everything in the house, including the external drive sitting next to the laptop. "Off-site" can just mean a cloud service, or a drive you leave at a relative's place.

Sync is not backup

This one catches people out constantly. If a folder is synced and you delete a file — or ransomware encrypts it — the sync obediently applies that change everywhere. It's a mirror, not a history. Real backup software keeps versions, so you can go back to how things were last Tuesday.

Most cloud services do keep deleted files for 30 days or so, which has saved plenty of people. Just don't rely on it as your plan.

Test it once

An untested backup is a guess. Once you've set something up, restore a single file from it. That's the whole test, it takes two minutes, and it's the difference between believing you're covered and knowing it.

If you'd like a hand setting this up so it runs without you thinking about it, get in touch — it's a short job and it's the best money you'll ever spend on IT.