Drive reliability stats
Price is only half the decision — a cheap drive that dies is not cheap. These pages pull together the largest published datasets on drive reliability and explain what they actually mean when you are choosing what to buy.
The three things worth knowing
- Model beats brand, decisively. Two Western Digital 16TB drives from the same generation differ by 3.4× in failure rate. Brand loyalty is not supported by the data.
- Big drives are currently the most reliable. The 20TB-and-above cohort now fails less than the fleet average, reversing years of received wisdom.
- Drives are lasting longer than the folklore says. Backblaze's 2025 re-analysis put peak failure age at over ten years, not the widely repeated three.
Hard drive failure rates: what 341,263 drives tell us
Backblaze runs over 341,000 drives and publishes every failure. Here is what the latest data actually says about which drives last.
Is Seagate really less reliable than WD?
The oldest argument in storage, checked against real numbers from a 341,000-drive fleet. The answer is not the one either camp expects.
Five SMART numbers that mean your drive is dying
Backblaze replaces a drive when any of five SMART attributes rises above zero. Here is what they are, and why a clean report is not the reassurance you think.
How long do drives last, and how to protect your data
Realistic lifespans for HDDs and SSDs, the warning signs of failure, and why every drive needs a backup.
Drive conditions explained: New, Used, Renewed and Warehouse
What each Amazon condition means — New, Used, Renewed, Warehouse and recertified — plus FBA vs FBM, and how buying from a euro-zone Amazon store actually works.
How to read failure-rate data
Two cautions apply to every number on these pages. First, population size matters: an annualised failure rate calculated from a few hundred drives is noise, which is why our tables show the drive count alongside every figure. Second, context matters: these fleets run 24/7 in climate-controlled racks with steady workloads. A drive in your desktop gets power-cycled, knocked and run warm, so treat this as strong evidence about drive mechanisms rather than a forecast for your own machine.
Whatever the statistics say, the practical answer never changes: no single drive is a backup, and RAID is not one either. Keep at least two copies of anything you would miss.