Backblaze Hard Drive Reliability Report 2025: The Most Reliable HDDs Ranked by Real-World Data

Every year, Backblaze releases one of the most closely watched storage studies in the industry. Unlike small lab tests or short-term reviews, this report analyzes real-world performance across massive data center environments.

For 2025, the numbers are based on 344,196 hard drives, covering 30 different models and totaling more than 115 million drive days of operation. That scale makes it one of the most statistically meaningful hard drive reliability reports available anywhere.

So how reliable are today’s hard drives? Which models performed best? And are larger-capacity drives really more dependable? Let’s break down the key findings from the 2025 Backblaze report.

Overall Hard Drive Failure Rate in 2025: 1.36%

The headline number for 2025 is clear:

Annualized Failure Rate (AFR): 1.36%

This marks the lowest overall failure rate since 2022 and confirms a positive trend in hard drive reliability.

Recent Failure Rate Trend:

• 2023: 1.70% (recent peak)
• 2024: 1.57%
• 2025: 1.36%

The direction is encouraging: failure rates are steadily declining.

Quarterly Breakdown (2025)

While the yearly average improved, performance fluctuated during the year:

• Q1: 1.42%
• Q2: 1.36%
• Q3: 1.55% (temporary spike)
• Q4: 1.13% (best quarter of the year)

A total of 4,317 drives failed across Backblaze’s entire fleet in 2025.

The strong Q4 finish helped push the annual average down and suggests improvements in fleet composition and hardware quality.

Bigger Drives Are Taking Over Data Centers

One of the most important trends in the 2025 report isn’t just reliability — it’s capacity migration.

Current Fleet Composition:

• 14TB–16TB drives: 52%
• 20TB+ drives: nearly 23%
• 12TB and smaller drives: 25% (shrinking rapidly)

Data centers are clearly transitioning toward high-capacity hard drives, and that shift is influencing overall reliability metrics.

The Arrival of 26TB Drives

In Q4 2025, Backblaze deployed its first 26TB model:

• WDC WUH722626ALE6L4
• 1,201 units installed
• 1 failure recorded
• AFR: 0.40%

While it’s too early to draw long-term conclusions, the early data is promising.

Why Larger Drives Are Improving Statistics

Newer high-capacity drives tend to:

• Use updated manufacturing processes
• Replace aging 8TB–12TB models
• Benefit from years of engineering refinement

As older, smaller drives are phased out, overall fleet reliability naturally improves.

Most Reliable Hard Drive Models in 2025

Several enterprise models stood out for their excellent reliability.

Top Performers

• Seagate ST16000NM002J
  • Only 1 failure
  • 466 units deployed
• WDC WUH722222ALE6L4
  • AFR: 0.47%
  • Over 44,000 drives in service (large sample size makes this highly significant)
• Toshiba MG08ACA16TA
  • AFR: 0.90%
  • Around 40,000 units

Best Q4 2025 Performers

• Seagate ST8000NM000A – Zero failures
• Seagate ST16000NM002J – Zero failures
• WDC WUH722222ALE6L4 – Q4 AFR: 0.23%

Key takeaway:
Recent high-capacity enterprise drives from Seagate, Western Digital, and Toshiba are performing well below the fleet average failure rate.

Drive age remains the single biggest risk factor.

Models With Higher Failure Rates (Context Matters)

Three models showed elevated failure rates — but each case has a specific explanation.

1. HGST HUH728080ALE600

• Q4 AFR: 10.29%
• Average age: 7.5 years
• Small fleet: 1,073 units

These drives are simply old. Backblaze ruled out temperature issues and suspects vibration sensitivity. Given their age, they are now being retired through normal lifecycle replacement.

This is a classic example of aging hardware rather than defective design.

2. Toshiba MG08ACA16TEY

• Q3 AFR spike: 16.95%
• Q4 AFR: 4.14%

The Q3 spike was linked to a firmware update operation conducted with Toshiba. The update artificially increased recorded failure events.

In other words, it wasn’t mechanical degradation — it was maintenance-related reporting.

3. Seagate ST10000NM0086

• Q4 AFR: 5.23%
• Average age: 95 months

Again, age is the dominant factor. Nearly 8-year-old drives naturally exhibit higher failure rates.

Should Consumers Use Backblaze Data to Choose a Hard Drive?

This is an important question.

Backblaze operates drives in:

• 24/7 environments
• High-density data centers
• Controlled cooling and vibration conditions

That’s very different from:

• Home NAS systems
• Gaming PCs
• Desktop workstations

So you shouldn’t directly translate a 1.36% AFR to consumer expectations.

However, the data is still valuable because it shows:

• Which models last long-term
• How failure rates evolve with age
• How newer high-capacity drives compare to older generations
• That modern enterprise drives are generally more reliable than aging 8TB–12TB models

For buyers building a NAS or upgrading storage in 2026, this long-term operational data can help narrow down reliable enterprise-grade options.

Hard Drive Prices in 2026: A New Factor

Another important development: hard drive prices have increased significantly since late 2025 — roughly 46% higher in some segments.

Much of this surge is tied to growing AI infrastructure demand, which is absorbing large-capacity enterprise drives.

That means timing matters. If you’re planning to expand storage, monitoring pricing trends is just as important as reviewing reliability statistics.

Final Thoughts:

The 2025 Backblaze report confirms something important:

Hard drive reliability is improving, especially as newer, high-capacity enterprise models replace aging hardware.

With a 1.36% annualized failure rate, 2025 represents one of the best years for data center HDD reliability in recent memory.

But the lesson remains clear:

• Age is the biggest predictor of failure.
• Newer 16TB–22TB enterprise drives show strong durability.
• Older 8TB–12TB models are increasingly reaching end-of-life.
• Data center data is informative — but not directly transferable to home users.

If you’re upgrading storage in 2026, choosing a modern, high-capacity enterprise drive from a reputable manufacturer is statistically safer than holding onto aging hardware.

And as storage demand continues to grow — especially with AI workloads — reliability will remain more important than ever.