Code-Memo

Backup strategies

The rule

RAID is not a backup. Snapshots are not a backup unless they are independent and recoverable.

3-2-1 guideline

• 3 copies of data
• 2 different media / systems
• 1 offsite (or offline/immutable)

What to back up

• Critical app data (databases, uploads)
• Config (/etc, infrastructure-as-code)
• Secrets (managed + recoverable; avoid plaintext copies)
• Logs (if required for audits/forensics)

Backup types

• Full: simplest restore, largest size
• Incremental: fastest daily backups, more complex restore chain
• Differential: middle ground

Tools (examples)

• rsync for file-based backups
• borg, restic for dedup + encryption
• DB-native backups (pg_dump, xtrabackup, etc.)

Testing restores

Regularly test:

• restore time (RTO)
• acceptable data loss (RPO)
• integrity (checksums)

Related

• Snapshotting
• Object storage concepts