Backups: the 3-2-1 rule

Hard drives fail. Phones get dropped in water. Laptops are stolen. Files get deleted by accident, or scrambled by a faulty update. It happens to nearly everyone eventually, and the only question is whether you have a backup when it does.

A simple rule keeps your files safe. It is called 3-2-1.

The rule#

• 3 copies of your data: the original and two backups.
• 2 different types of storage, such as your computer plus an external drive, so one kind of failure does not take out both.
• 1 copy off-site, somewhere other than your home, so a fire, flood or burglary cannot destroy everything.

What it looks like in practice#

For most people, a good setup is:

1. The original on your computer or phone.
2. A copy on an external drive that you plug in regularly, or that backs up automatically.
3. A copy in the cloud, using a backup or storage service you trust, which counts as the off-site one.

Photos, documents and anything you could not recreate matter most. Programs can be reinstalled, but a lost photograph cannot.

Automate it#

A backup you have to remember is a backup you will forget. Use the built-in tools your computer and phone offer, or a backup service, and set them to run on their own.

Test it#

A backup you have never restored is only a hope. Once or twice a year, try to open a file from your backup. Check that it works and that it is recent. It takes five minutes and can spare you from finding out the hard way.

One more thing#

A copy that syncs automatically, like a shared folder, is not always a backup. If you delete a file, the deletion can sync too. A real backup keeps older versions you can go back to.