Are Hard Drives Getting Better? Let’s Revisit the Bathtub Curve
Key Takeaways
- Backblaze's 13 years of drive data contradicts the traditional 'bathtub curve' model for hardware reliability.
- The data shows drive failures exhibit dips, spikes, and plateaus, rather than a predictable U-shaped failure rate.
- Hard drives, particularly in data center environments, are performing better and achieving longer longevity over time.
- The failure rate pattern is evolving, suggesting a flatter reliability profile rather than the classic failure curve.
- Comparing historical data requires accounting for factors like changes in drive pool size and data logging methods.
Backblaze has analyzed 13 years of continuous data from its Drive Stats dataset to challenge the reliability engineering standard known as the bathtub curve, which posits a predictable U-shaped failure rate over time. The company's real-world drive fleet data has consistently shown deviations, including dips, spikes, and plateaus, suggesting the neat story of early failures, calm middle age, and gentle decline no longer applies. Previous analysis in 2013 and 2021 already hinted that the curve was 'leaking,' with newer data showing fewer early failures and extended longevity. The conclusion drawn from the extensive dataset is that hard drives are getting better and lasting longer in data center environments. The article details how the analysis has evolved, noting complexities in comparing historical data sets due to changes in drive populations and logging methods over the years. Ultimately, the shape of reliability is becoming clearer, looking less like a bathtub and more like a low wall at the entrance to a shower.
