3-2-1 Backup Rule
A data protection strategy requiring three copies of data on two different media types, with one copy stored offsite.
Also known as: 3-2-1 Rule, Backup Strategy, Data Protection Rule
Category: Principles
Tags: backup, data-protection, knowledge-management, systems, best-practices
Explanation
The 3-2-1 Backup Rule is a widely-adopted data protection strategy that ensures data survival even in worst-case scenarios. The rule states you should maintain:
**3 copies of your data in total** - This includes the original plus two backups. Multiple copies protect against accidental deletion, corruption, or hardware failure.
**2 different storage media types** - Store backups on different types of media (e.g., internal hard drive, external SSD, cloud storage). This protects against media-specific failures.
**1 copy stored offsite** - Keep at least one backup in a different physical location. This protects against theft, fire, flood, or other disasters affecting a single location.
In knowledge management, this rule is critical because your notes and knowledge base represent years of accumulated thinking and work. Losing them would be devastating. Implementation options include:
- Local backups to external drives
- Cloud sync services (Dropbox, Google Drive, iCloud)
- Git repositories for version control
- Dedicated backup services (Backblaze, Syncthing to a NAS)
Remember: synchronization is NOT backup - it replicates mistakes and deletions. True backups should include versioning and be tested regularly.
Related Concepts
← Back to all concepts