3-2-1 Backup Rule: What It Is + How To Implement | Huntress

This document explains the 3-2-1 backup rule and its expanded 3-2-1-1-0 variant, outlining why multiple copies, diverse media, and an off-site immutable copy with regular testing are essential to recover from data loss or ransomware. It provides practical implementation steps—inventory and classification, selecting media and locations, scheduling/retention/encryption, testing restores, and integrating backups with detection and response—along with cloud-specific best practices and governance recommendations to ensure resilient recovery.