The 3-2-1 Backup Strategy for Homelabs

Data loss is not a matter of if, but when. Hard drives fail, ransomware attacks happen, and accidents occur. The 3-2-1 backup strategy is your insurance policy against data loss.

What is 3-2-1?

The 3-2-1 rule is simple:

• 3 copies of your data
• 2 different storage media types
• 1 offsite backup

Let's break down how to implement this in a homelab environment.

The First Copy: Primary Storage

Your primary data lives on your main storage system. In our homelab, we use:

• ZFS - For data integrity and snapshots
• Proxmox VE - For VM and container storage
• TrueNAS - For file storage and media

ZFS Configuration Example

# Create a mirrored pool
zpool create tank mirror /dev/sda /dev/sdb

# Enable compression
zfs set compression=lz4 tank

# Create datasets
zfs create tank/vms
zfs create tank/containers
zfs create tank/files

The Second Copy: Local Backup

Your local backup should be on different media from your primary storage. Options include:

• A separate NAS device
• External hard drives
• A dedicated backup server

Proxmox Backup Server

PBS is our go-to solution for VM and container backups:

# Example backup job in PBS
proxmox-backup-client backup \
  vm/100.pxar:/path/to/vm \
  --repository user@pbs:datastore

Automated Snapshots

Schedule regular ZFS snapshots:

# Create a snapshot
zfs snapshot tank/files@$(date +%Y-%m-%d)

# List snapshots
zfs list -t snapshot

The Third Copy: Offsite Backup

Offsite backup protects against physical disasters. Options include:

1. Cloud Storage - Backblaze B2, Wasabi, or AWS S3
2. Remote Location - A friend's house or office
3. Safety Deposit Box - For critical archives

Restic to Backblaze B2

# Initialize repository
restic -r b2:bucket-name:path init

# Backup
restic -r b2:bucket-name:path backup /path/to/data

# Prune old backups
restic -r b2:bucket-name:path forget --keep-last 7 --keep-weekly 4 --prune

Monitoring and Testing

Backups are worthless if they don't work. Implement:

1. Backup Monitoring - Alert on failures
2. Regular Test Restores - Quarterly at minimum
3. Documentation - Know your recovery procedures

Simple Monitoring Script

#!/bin/bash
BACKUP_DIR="/mnt/backups"
MAX_AGE=86400 # 24 hours

latest=$(find $BACKUP_DIR -type f -mtime -1 | head -1)

if [ -z "$latest" ]; then
  echo "ALERT: No recent backups found!"
  # Send notification
fi

Our Backup Stack

Here's what we use in our homelab:

| Layer | Tool | Destination | |-------|------|-------------| | VM/CT Backups | Proxmox Backup Server | Local NAS | | File Sync | Syncthing | Secondary NAS | | Offsite | Restic + rclone | Backblaze B2 | | Snapshots | ZFS | Local |

Key Takeaways

1. Automate everything - Manual backups don't happen
2. Test regularly - Untested backups are not backups
3. Encrypt offsite - Protect data in transit and at rest
4. Document recovery - Know how to restore before you need to

Remember: RAID is not a backup. Snapshots alone are not a backup. Only the 3-2-1 strategy gives you true data protection.