• A backup or data backup is a simple form of disaster recovery.
  • A backup system contains at least one copy of all data considered worth saving but there is better solution.
  • Peter Krogh introduced the 3-2-1 Backup Rule when he published his book, “The DAM Book: Digital Asset Management for Photographers” in 2005.
  • Also the U.S. Federal Cybersecurity Agency: Cybersecurity and Infrastructure Security Agency (CISA) recommends that individuals and businesses use the 3-2-1 strategy.

3-2-1 Backup Rule

- 3: Create one primary backup and two copies of your data.
- 2: Save your backups to two different types of media.
- 1: Keep at least one backup file offsite.
  • 3-2-1 Rule is enough for most of the people but more expensive backup strategies also exists like 3-2-1-1-0 and 4-3-2 for more details look into articles below.