The Long-Term Case for HDD Storage

Why HDDs Matter 

Hard disk drives remain the cornerstone of data center storage—and the indispensable infrastructure that makes AI possible. Analysts and enterprise customers expect sustained growth in HDD unit volumes and capacity shipments, driven by the exponential rise in global data generation—projected to more than triple from 173.4ZB in 2024 to 527.5ZB in 2029.¹ This demand is being accelerated by AI, which requires massive capacity to store training data, images, and video at unprecedented scale. 

Storage Is Not One-Size-Fits-All 

Data center workloads have diverse needs. HDDs deliver cost-efficient capacity at scale for “warm” and “cold” workloads that don’t require instant access. SSDs excel for high-access, latency-sensitive data. Tape, which still holds ~10% of cloud capacity, underscores the reality that storage is a tiered ecosystem. The lesson: AI and cloud infrastructures depend on the right balance of storage media, and HDDs provide the essential layer of scalable, reliable capacity. 

TCO Is the Decider 

When selecting storage, operators optimize for total cost of ownership (TCO) across all storage tiers within the data center. Acquisition cost, power efficiency, density, performance, and product lifecycle all factor in. Enterprise HDDs hold a decisive advantage: IDC reports a 5x–10x $/TB premium for SSDs versus HDDs,² with comparable power efficiency. In large-scale environments, those economics compound—making HDDs the indispensable infrastructure that keeps AI viable and sustainable. 

Reliability at Scale 

Capacity alone isn’t enough. At hyperscale, the true differentiator is reliability. Hyperscalers demand storage that performs predictably at exabyte scale, under relentless workloads, with minimal failure rates. Western Digital’s innovations—from HelioSeal^® to OptiNAND™ and UltraSMR—are proven in production at scale, delivering both the economics and the dependability hyperscalers rely on. It’s why the world’s largest data-driven companies continue to heavily invest in HDDs they can trust. 

Economics That Endure 

NAND flash costs track bits per wafer; HDD costs track areal density per platter. Both technologies are advancing at similar rates,³ ensuring the TCO gap will persist. This isn’t a temporary cost advantage—it’s a structural, long-term reality. As AI and data creation surge, HDDs remain the economic foundation for scaling storage sustainably. 

Market Outlook 

The storage market is expanding. HDDs, SSDs, and even tape are all growing to meet surging demand. But flash-only configurations cannot displace HDD at hyperscale. In fact, they provide different value in a multi-tiered storage ecosystem. Industry leaders like Google, with its Colossus storage architecture, validate that HDDs remain central to modern, AI-ready infrastructure. Customers prioritize reliable capacity they can deploy confidently at scale, and HDDs deliver exactly that. 

Conclusion 

AI and cloud adoption are accelerating, and storage must scale with them. SSDs will continue to lead in ultra-high-performance applications, and HDDs will remain the backbone of cost-efficient, reliable capacity at scale. As the indispensable infrastructure for AI, HDDs ensure that the world’s most data-intensive workloads are not just possible, but economically and operationally sustainable. 

1. Source: Worldwide IDC Global DataSphere Forecast, 2025–2029, #US53363625, May 2025 
2. Source: IDC Worldwide 2024–2028 Enterprise HDD: Market Overview, #US52411324, July 2024 
3. TechInsights NAND Market Report Q3 2024; A new Advanced Storage Research Consortium HDD Technology Roadmap