What the Backblaze 2025 Drive Stats Report Tells You About Your Storage Array

Every February, Backblaze publishes its annual Drive Stats report, one of the only publicly available, large-scale, real-world datasets on hard drive reliability. The 2025 edition covers 344,196 drives across 30 models, representing over 115 million cumulative drive-days of operational data. It is the kind of dataset that, if you are making storage procurement decisions, you cannot afford to ignore.

This article walks through what the data shows, what it does not show, and what it means for organizations operating or planning storage arrays in Bosnia and Herzegovina and the wider Western Balkans region.

The Headline Numbers

Backblaze’s overall Annualized Failure Rate (AFR) for 2025 came in at 1.36%, down from 1.55% in 2024 and the lowest figure recorded since 2022. Q4 2025 was even stronger, posting a quarterly AFR of 1.13%. Across a fleet of over 344,000 drives running in professional data center conditions, roughly one in every 73 drives could be expected to fail within a given year.

That sounds reassuring. It is not the whole picture.

The Models That Stood Out — For Better and Worse

The Reliable End

Several models recorded zero or near-zero failures across Q4 2025:

• Seagate ST8000NM000A 8TB — zero failures recorded
• Seagate ST16000NM002J 16TB — zero failures, only one failure for the entire year
• HGST HMS5C4040BLE640 4TB — a consistent performer across multiple consecutive Drive Stats reports
• WDC WUH722626ALE6L4 26TB — Backblaze’s first 26TB drive in service, one failure across Q4 2025 despite being brand new to the fleet

The Problem Models

Three models attracted attention for elevated failure rates in Q4 2025:

• HGST HUH728080ALE600 8TB — 10.29% AFR in Q4. Backblaze investigated and ruled out temperature and airflow as contributing factors. The working theory points to vibration sensitivity combined with age-related wear; this model is approximately 7.5 years old.
• Seagate ST10000NM0086 10TB — 5.23% AFR. Backblaze notes this is consistent with end-of-life behaviour for this model.
• Toshiba MG08ACA16TEY 16TB — 4.14% AFR in Q4, improving from a concerning 16.95% in Q3 2025. The Q3 spike was traced to firmware-level collaborative work between Backblaze and Toshiba; the normalization in Q4 confirms this.

What the Data Does Not Tell You

The Backblaze dataset is invaluable but it has context that organizations must account for before drawing procurement conclusions.

1. These are data center drives in controlled environments. Backblaze operates purpose-built data centers with managed temperature, humidity, airflow, and vibration dampening. Drives in smaller server rooms, unmanaged racks, or environments with intermittent power quality operate under materially different conditions. The 1.36% fleet AFR reflects best-case operating conditions for mechanical storage.
2. Age drives the outliers. The HGST 8TB model that hit 10.29% in Q4 is approximately 7.5 years old. Older smaller-capacity drives (sub-12TB, 6+ years) showed AFRs that frequently exceeded 10% in the quarterly breakdowns. This is not a manufacturer quality problem — it is physics. Drive failure probability rises steeply with age, particularly after the five-to-seven year mark in continuous operation.
3. Fleet size affects the numbers. Seagate accounts for the majority of drives in the Backblaze fleet, which can make manufacturer-level comparisons misleading. Western Digital maintained sub-1% average failure rates, but operates a significantly smaller number of drives in Backblaze’s environment. Smaller sample sizes mean individual model outcomes carry disproportionate weight.
4. High-capacity drives are becoming dominant. Backblaze’s 2025 report reflects an accelerating shift toward 16TB, 20TB, and now 26TB drives. The cost-per-gigabyte for large-capacity enterprise drives continues to fall, while smaller-capacity drives are increasingly difficult to source. Organizations still running storage arrays built around 8TB or 10TB drives should be planning capacity refresh cycles, not just reactive replacements.

What This Means for Your Storage Array

1. AFR is Not Your Risk — Array Architecture Is

A 1.36% annual failure rate per drive sounds manageable. In a storage array of 60 drives, a reasonable size for a mid-range enterprise NAS or SAN, the probability of at least one drive failing within any given year approaches near-certainty under statistical modelling. The question is never whether a drive will fail; it is whether your array architecture handles the failure without data loss or service interruption.

RAID remains the foundational answer, but RAID level selection matters enormously:

• RAID 5 tolerates one drive failure. During rebuild, a second drive failure means total data loss. With large-capacity drives, rebuild times now frequently exceed 24 hours — during which the array runs with no fault tolerance.
• RAID 6 tolerates two simultaneous failures and provides meaningful protection during long rebuild windows. For arrays using 16TB+ drives, this is the minimum sensible configuration for production data.
• RAID 10 provides high redundancy and faster recovery at the cost of 50% usable capacity. Appropriate for databases, virtualization hosts, and environments where rebuild time is itself a risk.

2. Drive Age Is an Operational Risk, Not Just a Hardware Metric

The HGST 8TB case study is instructive. A drive with acceptable failure rates for most of its life crosses into double-digit AFR territory at 7.5 years. Organizations that deploy hardware and leave it without structured lifecycle management are accumulating silent risk.

A structured refresh cycle — typically five years for production storage in critical environments — is not an arbitrary vendor sales tactic. It reflects the real-world failure probability curves documented in more than a decade of Backblaze data.

3. Mix Your Manufacturers, Not Your Models

The Backblaze data consistently shows that individual model performance varies significantly within a single manufacturer’s lineup. The appropriate conclusion is not “buy only Brand X” — it is “understand which specific models are performing, and avoid mixing drive models within a single array.”

Mixing models within an array creates inconsistent rebuild behavior, complicates spare drive management, and makes failure pattern monitoring significantly harder. Standardize model selection within each array and maintain documented spare inventory.

4. High-Capacity Drives Require Updated Infrastructure Assumptions

26TB drives are now entering production environments. At that capacity, a single drive failure in an unprotected or poorly configured array represents an enormous data exposure event. Simultaneously, the rebuild time for a 26TB drive on a typical SAS/SATA controller can extend well beyond 48 hours during which the array operates with reduced redundancy.

Organizations moving to high-capacity drives need to audit their controller bandwidth, spare capacity policies, and backup refresh intervals alongside the drive procurement decision.

The Role of Backup in a World Where Drives Always Fail

This is the point at which the Backblaze data becomes directly actionable: RAID is not backup.

RAID protects against unplanned drive failure. It does not protect against logical corruption, ransomware, administrator error, controller failure, or site-level events. A storage array — regardless of how well configured — is one component of a data protection architecture, not the architecture itself.

A complete storage resilience posture for a Bosnian or Western Balkans organization operating under the country’s Personal Data Protection Law requires:

• Redundant local storage (RAID 6 or RAID 10 for production arrays)
• Automated backup to a separate storage target, ideally offline or air-gapped
• Off-site or cloud replication for disaster recovery
• Tested restore procedures — documented, scheduled, and verified

Backup solutions including Veeam and Acronis integrate directly with major storage platforms and provide the scheduling, verification, and reporting infrastructure that transforms a backup policy into a provable protection capability.

Applying This to HPE, Dell EMC, and Supermicro Environments

Enterprise storage platforms from HPE, Dell EMC, and Supermicro operate with hardware RAID controllers, hot-spare management, and proactive monitoring tools that go significantly beyond what the Backblaze data captures. These platforms:

• Monitor SMART data and predictive failure indicators in real time, triggering replacement workflows before a drive actually fails
• Support hot-spare configurations that initiate automatic rebuild without manual intervention
• Provide array-level health dashboards with alerting integration
• Operate with drives that have been validated and certified for the specific platform — including firmware alignment that consumer or non-certified drives do not provide

This is the meaningful difference between a purpose-built enterprise storage array and an assembled storage server: not just the hardware, but the operational tooling around it.

Practical Takeaways

If you are operating or planning storage infrastructure in Bosnia and Herzegovina:

• Audit the age of your current drives. Any drive over five years in production use should be in an active replacement plan, not a reactive one.
• Review your RAID configuration against current drive sizes. Arrays built around RAID 5 with 12TB+ drives carry rebuild-window risk that RAID 6 eliminates.
• Standardize your drive model selection. Avoid mixing models within a single array, and maintain a documented spare.
• Test your restores. A backup that has not been restored is an assumption, not protection.
• Plan capacity cycles, not just failure responses. High-capacity drives are becoming the standard; infrastructure designed around smaller drives will require refresh, and planning it is cheaper than emergency procurement.

How Zerick Can Help

Zerick d.o.o. is an authorized service provider for HPE, Dell EMC, and Supermicro storage platforms, with deployment and support capabilities across Bosnia and Herzegovina and the Western Balkans. Our team designs, supplies, deploys, and supports storage environments for government institutions, banking sector organizations, automotive operations, and municipalities — environments where storage failure is not a recoverable event.

If your storage infrastructure is due for a lifecycle review — whether that means a capacity refresh, a RAID architecture assessment, or a backup posture audit — we can provide a grounded technical evaluation based on what is actually running in your environment.

Data sources: Backblaze Drive Stats for 2025 (published February 12, 2026), Backblaze Drive Stats for Q3 2025, Backblaze Drive Stats for Q2 2025, Backblaze Drive Stats for Q1 2025.