Hard drive reliability has improved in 2025, according to Backblaze’s latest annual analysis, which tracks failure rates across a fleet of over 340,000 drives. The company’s 2025 annualized failure rate (AFR) dropped to 1.36%, a decline from 1.55% in 2024 and matching the lowest rates observed since 2022. This trend reflects not just incremental improvements but a broader shift in storage infrastructure—one where high-capacity drives now dominate, reshaping how data centers approach reliability metrics.

The data underscores a key tension in modern storage: as drive capacities grow—from 12TB to 26TB models—the sheer volume of data stored per unit increases, but so does the potential for failure. Yet Backblaze’s findings suggest that, when managed at scale, these drives perform comparably to their smaller counterparts, provided they meet rigorous operational thresholds.

Why This Matters

Backblaze’s dataset is one of the most extensive longitudinal studies of hard drive reliability in production environments. Spanning 13 years, it provides a rare, real-world perspective on how drives behave over time, across different manufacturers, and under varying workloads. For enterprises, this data serves as a benchmark for procurement decisions, helping them balance cost, capacity, and risk.

This year’s report is particularly notable for two reasons

  • The 26TB Western Digital model (WDC WUH722626ALE6L4) made its debut in Backblaze’s fleet, marking the first time a drive of this capacity has been deployed at scale. With just one failure in its first quarter, it suggests early promise—but long-term reliability will depend on sustained performance.
  • Several models demonstrated exceptionally low failure rates, including the Seagate ST16000NM002J (0.22% AFR) and Toshiba MG10ACA20TE (0.59% AFR), reinforcing that modern enterprise drives can achieve near-flawless operation when deployed in controlled environments.

Key Findings from 2025

The 2025 report breaks down reliability into three lenses: quarterly performance, full-year AFR, and lifetime trends. Each offers a different perspective on how drives behave under real-world conditions.

Quarterly Highlights (Q4 2025)

Backblaze’s Q4 analysis covered 337,192 drives, excluding boot drives and those that didn’t meet minimum deployment criteria. Two new models entered the fleet

  • Seagate ST16000NM000J (16TB) – Deployed with 112 drives, recorded one failure in its first quarter.
  • Western Digital WUH722626ALE6L4 (26TB) – The first 26TB drive in production, with 1,201 units and just one failure—a strong early indicator.

Notably, some drives achieved zero failures in Q4, including

  • Seagate ST8000NM000A (8TB)
  • Seagate ST16000NM002J (16TB)

However, a few models stood out for elevated failure rates, warranting deeper investigation

  • HGST HUH728080ALE600 (8TB) – 10.29% AFR, attributed to potential vibration sensitivity in a concentrated deployment. Backblaze noted that environmental factors like temperature were ruled out.
  • Toshiba MG08ACA16TEY (16TB) – Improved from a 16.95% AFR in Q3 to 4.14% in Q4, thanks to firmware updates. The trend suggests that proactive fixes can mitigate risks in aging hardware.

Full-Year AFR (2025)

The annual AFR of 1.36% reflects a 12% improvement over 2024, continuing a downward trajectory that began in 2023. The report analyzed 344,196 drives, with the following standout performers

Hard Drive Reliability Improves as Backblaze Fleet Shifts to High-Capacity Models
  • HGST HMS5C4040BLE640 (4TB) – 0.49% AFR, with just 5 failures across the year.
  • Seagate ST16000NM002J (16TB) – 0.22% AFR, the lowest among 16TB models.
  • Western Digital WUH722222ALE6L4 (22TB) – 0.47% AFR, demonstrating reliability at scale with 44,577 drives deployed.

Larger drives, once considered higher-risk due to their complexity, now account for 75% of Backblaze’s fleet by capacity, a shift that aligns with industry trends toward higher-density storage. The 20TB+ segment alone represents 22.81% of the total, up from previous years.

Backblaze’s lifetime AFR remains stable at 1.30%, a figure that has held steady across multiple reporting cycles. This consistency suggests that while individual models may experience volatility, the overall reliability of the fleet is improving incrementally. The report highlights

  • HGST HMS5C4040BLE640 (4TB) – 0.40% lifetime AFR after 82.8 months of average age, proving long-term durability.
  • Seagate ST16000NM001G (16TB) – 0.69% lifetime AFR, with 35,231 drives and an average age of 38.2 months.
  • Toshiba MG07ACA14TA (14TB) – 1.03% lifetime AFR, deployed in 39,387 units over 59.8 months.

The Toshiba MG11ACA24TE (24TB) model, newly included in the lifetime analysis, has 4,806 drives in service with a 0.68% AFR, though its long-term performance remains to be seen.

What This Means for Enterprises

The data reinforces several key takeaways for data center operators

  • Higher capacity does not inherently mean higher risk. Backblaze’s fleet now leans heavily toward 14TB–16TB drives, which collectively show lower AFRs than many smaller models. This challenges the assumption that bigger drives are less reliable.
  • Firmware and environmental factors play critical roles. Models like the Toshiba MG08ACA16TEY saw dramatic improvements after firmware updates, while others (e.g., HGST HUH728080ALE600) were flagged for potential vibration issues in specific deployments.
  • Long-term reliability is improving. The 1.30% lifetime AFR is a testament to advancements in drive design, though enterprises should still monitor models as they age, particularly those nearing end-of-life.
  • New capacities enter the mainstream quickly. The 26TB Western Digital model is already in production, suggesting that as reliability data accumulates, even larger drives will become standard.

For storage providers and enterprises evaluating drives, Backblaze’s report serves as a real-world stress test. The shift toward higher-capacity models reflects both technological progress and a growing confidence in their reliability—provided they are deployed in environments optimized for their operational needs.

The full dataset, available in Backblaze’s report, offers granular insights for those seeking to benchmark specific models. As drives continue to evolve, so too will the metrics that define their success.