The homelab uses a layered backup approach, split into two independent
tracks: NAS user content, and Proxmox VM/LXC backups. Both follow a
3-2-1-style rule — multiple copies, multiple media types, at least one
copy on a different machine.
NAS user content — four layers
| Layer | Target | Frequency | Purpose |
|---|
| Snapshots | Synology, built-in | Hourly | Fast recovery of accidentally deleted files |
| Local backup | USB drive attached to the NAS | Daily | Local versioned backup, independent of the NAS disks |
| Offsite sync | External drive on a Raspberry Pi in a different room | Weekly | Geographically separated copy within the flat |
| Cloud archive | Cloud storage | Continuous | Off-site copy for worst-case scenarios (fire, theft) |
Proxmox VM/LXC backups — three copies, two machines
| Copy | Target | Frequency |
|---|
| 1 — original | Proxmox host itself | Daily |
| 2 — primary offsite | Synology NAS (different machine) | Daily, right after copy 1 |
| 3 — secondary offsite | Raspberry Pi backup target, different room | Daily (skipped one day/week to avoid network contention with the weekly NAS sync) |
Design principles
- Backups always cross at least one machine boundary — nothing is considered "backed up" if it only lives on the source machine's local disk.
- Weekly and daily jobs are scheduled to avoid saturating the internal power-line network link used by the offsite backup target.
- All scheduled jobs ping a dead-man's-switch monitoring service; a missed backup triggers an alert.
- Power to the offsite drive is only switched on for the duration of its weekly sync, to save power and extend disk life.