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3-2-1 backup rule

Backups and Business Continuity

The 3-2-1 rule calls for three copies of your data, on two different types of storage, with one copy off-site. It reduces the risk that a single incident will destroy every copy.

Examples for small businesses

  • An accountancy practice keeps its working files on a server, a backup on separate local storage and another backup in the cloud.
  • A dental clinic keeps its records on a server, backs them up to an external drive and keeps an off-site copy in Synology C2.
  • An architect keeps projects on a computer and a shared NAS, with a separate backup in cloud storage.

Common mistakes

  • Keeping all copies in one building, where the same incident could affect them all.
  • Failing to test whether the backups can be restored.

Related terms

FAQ

Why keep a copy off-site?
It gives you a recovery option if a fire, theft or other incident affects your premises.
Can a cloud backup count as the off-site copy?
Yes. It should be independent of your local copies, protected appropriately and recoverable even if your local equipment is unavailable.