3-2-1: three copies of important data, on two media types, with one copy offsite (or in a separate failure domain).

Replication is not backup. RAID or Ceph keeps disks alive — it won't undo accidental deletes or ransomware.

Homelab stack (typical)

1. Snapshot backups for VMs/containers (e.g. Proxmox Backup Server)
2. File storage with ZFS snapshots for large media and documents
3. Test restores occasionally — backups you never restore are guesses

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