Which backup strategy is best practice for data resilience, typically described as three copies on two media with one offsite?

Which backup strategy is best practice for data resilience, typically described as three copies on two media with one offsite?

• A. Full Backup
• B. Incremental Backup
• C. Differential Backup
• D. 3-2-1 Backup Rule

Answer: (D)

The best practice for data resilience is the 3-2-1 backup rule: three copies of data on two different media with one offsite. Having three copies means you’re protected if one copy is corrupted, overwritten, or accidentally deleted, giving you a clean fallback. Using two different media types reduces the risk that a single media failure will take both copies down, and keeping one copy offsite shields you from local disasters like fires, floods, or ransomware attacks targeting on-site backups. In practice, you’d keep the primary data where it’s used, back up to a local secondary medium, and replicate or store a copy at a remote offsite location (such as cloud storage or a separate facility). Regular restore testing and ensuring the offsite copy remains isolated and up to date are important to make this strategy effective. The other backup terms describe how backups are created over time (full, incremental, differential) but don’t address the essential redundancy and geographic separation that the 3-2-1 rule provides.

The best practice for data resilience is the 3-2-1 backup rule: three copies of data on two different media with one offsite. Having three copies means you’re protected if one copy is corrupted, overwritten, or accidentally deleted, giving you a clean fallback. Using two different media types reduces the risk that a single media failure will take both copies down, and keeping one copy offsite shields you from local disasters like fires, floods, or ransomware attacks targeting on-site backups. In practice, you’d keep the primary data where it’s used, back up to a local secondary medium, and replicate or store a copy at a remote offsite location (such as cloud storage or a separate facility). Regular restore testing and ensuring the offsite copy remains isolated and up to date are important to make this strategy effective. The other backup terms describe how backups are created over time (full, incremental, differential) but don’t address the essential redundancy and geographic separation that the 3-2-1 rule provides.