The three backup methods: what each one actually does
Cloud backup (Backblaze, iDrive, OneDrive, Google One) uploads your data to remote servers over the internet. It protects against physical disasters — if your house burns down, your files survive. The downside: uploads are slow (100GB can take 10–24 hours on a typical 50 Mbps upload connection) and the cost compounds over time. Backblaze Personal Backup is $9/month for unlimited storage; Google One runs $3–10/month for 200GB–2TB. A NAS (network-attached storage) is a box on your home network containing multiple hard drives with RAID redundancy. A Synology DS223 2-bay unit costs $300 and fits two 4TB drives ($80 each), giving you 4TB of protected storage accessible from any device on your network. Transfers run at 100–120 MB/s over Gigabit Ethernet — vastly faster than cloud. But it sits in your home, meaning a house fire takes it and your computer simultaneously. External hard drives are the cheapest option per TB: a 4TB Seagate Portable runs $80–100. Transfer speed via USB 3.0 is 100–150 MB/s — fine for manual backups. The limitation is manual operation: you must physically plug in the drive and run the backup. Drives left in a drawer fail silently; drives carried in a bag are at risk of damage.
5-year total cost of ownership: cloud vs NAS vs external
Cloud (2TB, Backblaze $9/month): $540 over 5 years, then ongoing. You pay indefinitely and never own anything. NAS (Synology DS223 + 2×4TB WD Red Plus drives): ~$460 upfront, then ~$50 every 5 years for drive replacement. Total 5-year cost: ~$510. After year 5, additional cost is only drive replacements — no subscription. External drive (4TB Seagate Portable): $90 upfront, replace once in 5 years: $180 total. Cheapest by far, but no automation and no local network access. The math favors NAS if you want speed and automation. It favors external drives if you only need cheap cold storage. Cloud makes financial sense only if you value off-site protection and don't want to manage hardware. Most home users with >1TB of data spend less long-term with a NAS + one external drive than with any cloud subscription at equivalent capacity.
Speed comparison: which backup method is fastest?
NAS via Gigabit Ethernet is the fastest local backup option. A Synology NAS with WD Red drives sustains 110–120 MB/s sequential writes — 100GB transfers in about 15 minutes. With a 2.5 Gigabit network (newer NAS models and motherboards support this), speeds reach 270–300 MB/s. External drives via USB 3.0 sustain 100–150 MB/s — comparable to NAS for the initial transfer, but you must physically connect the drive. Time Machine and Windows Backup handle this automatically when the drive is connected. Cloud is limited by your upload speed. On a 100 Mbps upload connection (high for home internet), 100GB uploads in about 2.2 hours. On a typical 20 Mbps upload, it takes 11 hours. Initial cloud backup of a full computer (500GB–1TB) often takes several days.
Disaster scenarios: what survives what
House fire or flood: Cloud survives (data is off-site). NAS is destroyed. External drive is destroyed unless kept off-site. This is the single strongest argument for cloud backup — no local backup survives a total home loss. Hard drive failure: NAS survives (RAID 1 or RAID 5 redundancy keeps data intact even when one drive fails). Cloud survives. External drive does not protect against the failure of the primary drive — it only protects if you've recently backed up to it. Accidental file deletion: Cloud (with version history — Backblaze retains 1-year history) is the best recovery option. NAS with snapshot support (Synology Btrfs volumes) also catches this. External drives catch it only if the deletion happened after your last manual backup. Theft: Cloud survives. NAS survives if not stolen (home office theft usually doesn't include server equipment). External drive is often stolen with the laptop.
The 3-2-1 rule: the backup strategy that covers everything
The backup industry standard is the 3-2-1 rule: 3 copies of your data, on 2 different media types, with 1 copy off-site. For a home user, this translates to: (1) your primary drive, (2) a NAS or external drive at home, and (3) cloud backup. This covers every disaster scenario — hardware failure, accidental deletion, and physical disaster all have a recovery path. A practical implementation: Time Machine or Windows Backup runs daily to a NAS. The NAS runs a nightly sync to Backblaze ($9/month). One external drive lives at a relative's house or office and rotates monthly. This costs ~$460 upfront for the NAS, $9/month cloud, and $90 for the off-site drive — roughly $570 first year, then $108/year ongoing.
Recommended setup by user type
Casual home user (documents, photos, ~200GB): External drive + iCloud or Google Photos. $90 + $3/month. Simple, automatic, covered for hardware failure and basic cloud protection. Photographer or video creator (1–4TB active data): NAS 2-bay + Backblaze. The NAS gives instant access to files; Backblaze protects against fire/theft. Budget: $460 NAS + $9/month. Home office or freelancer (irreplaceable client work): NAS + cloud + monthly off-site drive rotation. Full 3-2-1 coverage. Budget: ~$550 upfront + $9/month. Student (documents + code, ~50GB): GitHub for code (free), Google One 200GB ($3/month), and one $40 USB drive for Time Machine. Simplest viable solution.