Backups with the 3-2-1 rule

Hard drives fail, laptops get stolen, malware encrypts data. The question isn’t whether something will happen, but whether you’ll have a working backup when it does. The 3-2-1 rule is a simple, proven benchmark.

The rule in one sentence

• 3 copies of your data: the original and two backups.
• 2 different types of storage, e.g. a NAS in the office and cloud storage.
• 1 copy off-site – so a fire or burglary can’t hit everything at once.

What matters in practice

A backup is only as good as its restore. Check regularly that you can actually recover single files and whole systems. And keep at least one copy disconnected from the network or immutable – otherwise ransomware encrypts the backup as well.

Also keep several versions, known as snapshots. If an error or an infection is only noticed days later, the latest backup is often affected already. With older versions you simply go back to a point in time before that.

The off-site copy should always be encrypted. If it falls into the wrong hands, attackers without your personal key see nothing but an unreadable heap of data.

Automate as much as possible: a backup you have to remember will eventually be forgotten.

For our clients, our backup in the EU takes care of this: backups run automatically to our servers in the EU – so the off-site copy is done without you having to think about it.