Backup retention

GFS scheme

3-2-1-1-0 check

• 3 Three copies of the data: production plus two backups
• 2 On two different media or storage systems
• 1 One copy offsite, in another building or region
• 1 One copy offline, air-gapped or immutable
• 0 Zero errors: backups verified and restores tested

0 of 5 gaps remain

3-2-1 is usually credited to Peter Krogh (The DAM Book, 2009). The extra 1 (offline or immutable, against ransomware) and 0 (verified restores) are a later industry extension popularised by Veeam. Press a rule to mark it as met.