What is the 3-2-1 backup rule?
3 copies: Your original + 2 backups (so if one fails, you still have 2 other copies). 2 media types: One copy on an external SSD, one on a different external HDD or cloud service (protects against drive brand defects or tech-specific failure). 1 offsite: One copy stored away from home or in cloud (protects against fire, theft, ransomware that spreads across your entire network). Example: Photos on your laptop → USB external SSD backup → Cloud backup (Google Drive, Backblaze). If your laptop dies, USB is onsite. If ransomware hits your network, cloud copy is offsite and untouched.
Best setup: NAS + External HDD + Cloud
Most reliable for photos/documents: 1. Original: Photos on Mac/PC 2. Backup 1: NAS (Synology DS920+ with RAID): Automatic daily backup via Time Machine (Mac) or File History (Windows) 3. Backup 2: External USB SSD or HDD for weekly offline backup (disconnected when not in use — prevents ransomware spread) 4. Backup 3 (Offsite): Backblaze, Crash Plan, or Google Drive sync for cloud copy Cost: NAS $400–500, External HDD $100–150, Cloud $10–15/month = ~$550 one-time + $120/year.
Budget setup: Dual external HDDs + Cloud
If budget is tight: 1. Original: Photos on laptop 2. Backup 1: External HDD (4TB WD Red) connected always 3. Backup 2: Second external HDD (4TB Seagate Barracuda) connected weekly for backup (then disconnected) 4. Backup 3: Backblaze or Google Drive Cost: Two external HDDs $100–150 total, cloud $10–15/month = ~$150 one-time + $120/year. Much cheaper than NAS.
Protection against ransomware
Ransomware spreads across network backups (NAS connected to your network). Solution: Keep one backup offline and disconnected. Connect weekly, run backup, then disconnect. For critical data: External HDD disconnected 99% of the time. Cloud backup with versioning (Backblaze, Google One) retains 30 days of deleted files — if ransomware hits, restore from 3 weeks ago.