Hard disk drives (HDDs), once dismissed as "relics of a bygone era" compared with solid-state drives (SSDs), are enjoying a second heyday in the age of artificial intelligence (AI). They offer a lower-expense alternative for storing the explosively growing data needed for AI training and operations. As AI corporations begin enhancing model performance by not discarding data needed for AI models and instead keeping it on HDDs, HDDs have earned the nickname "data vault" of the AI era.
Compared with SSDs, which have long been favored as storage for data centers, HDDs are standing out for "price competitiveness" and "ultra-high-capacity data storage." SSDs boast overwhelmingly faster speeds with less noise and heat than HDDs, but as the data AI must handle grows exponentially, HDDs—offering lower prices and the ability to store ultra-high-capacity data of 30 terabytes (TB) or more—have become more important.
Stefan Mandl, Western Digital's global head of sales and marketing (vice president), said in a written interview with ChosunBiz on the 30th, "The faster AI adoption accelerates, the more customers need high-performance storage," adding, "Western Digital provides solutions that ensure long-term performance and durability while efficiently managing expense and energy use."
Western Digital is experiencing steep growth in results in step with surging HDD demand. Western Digital is the leading corporation in the HDD market. It holds about a 42% share, splitting the market with Seagate. Western Digital supplies HDDs to global big tech corporations including Google, Microsoft, Meta and Amazon.
In line with HDD demand, Western Digital's results have entered a growth phase. In fiscal year 2025 (July 2024–June 2025), the company achieved record results, with revenue surging 51% year over year to $9.52 billion (about 14.3656 trillion won) on explosive demand for high-capacity HDDs and SSDs used in AI data centers. Western Digital declared this year's supply "sold out" and said demand for long-term contracts through 2028 has increased.
Western Digital said it will target the market with products that maximize power efficiency while increasing storage capacity. The maximum capacity of Western Digital products released so far is 32TB. Mandl said, "We will begin mass production in the second half of this year of a product that expands capacity to 40TB without increasing power consumption. We aim to expand (capacity) to 100TB by 2029," adding, "We will support customers so they can flexibly adopt data storage devices according to the roadmap." The following is a Q&A with Mandl.
—What added value can Western Digital's HDDs create in the AI era? How is the role of HDDs changing?
"HDDs are essential for large-scale AI implementation. Training large-scale AI models on massive data requires enormous resources, so storage is needed that can provide large capacity reliably and withstand long hours of intensive workloads. HDDs are suitable storage for the large-scale data center environments AI requires in terms of expense efficiency and scalability.
Market research firm IDC expects about 80% of cloud storage to still be HDD-based in 2029. Western Digital helps stably maintain long-term performance and durability while efficiently managing data center operating expense and energy use."
—With a significant portion of revenue concentrated in data centers and cloud, how is the HDD business strategy being reorganized?
"As we enter the AI era, it is true that customer requirements for HDDs have diversified. To operate AI data centers, in addition to the performance to safely store massive data, technology is needed to minimize power and resolve data bottlenecks.
When developing storage technology, Western Digital focuses on five requirements: capacity to handle exploding data growth, reliability to support AI stably, performance to resolve data bottlenecks, power efficiency, and total cost of ownership (TCO) optimization for expense reduction. We have demonstrated this to customers and are pursuing collaboration through multi-year contracts.
—In the data center and cloud market, what differentiates you from competitors?
"'Top capacity' and 'power efficiency.' Western Digital is preparing the industry's highest-capacity products. We are conducting quality tests of the world's highest-capacity 40TB HDD with two customers and plan mass production in the second half of this year. In 2029, we will launch a 100TB product. We also have solutions that can maximize power efficiency as well as capacity. Western Digital will flexibly respond to the market by simultaneously launching energy-enhanced perpendicular magnetic recording (ePMR), which improves the reliability of data storage, and heat-assisted magnetic recording (HAMR), which maximizes storage capacity."
—What next-generation products are you preparing?
"Customers are not simply buying the drive itself. They comprehensively consider how quickly they can secure deployable capacity, whether reliability is ensured to operate stably at scale, how the power efficiency is, and whether the price is reasonable. Because customers' AI models and applications vary, the required combinations of capacity, performance and power efficiency also differ.
To meet these customer needs quickly and flexibly, we are advancing HDD technology and expanding the HDD platform. We announced a product roadmap to customers to increase bandwidth—meaning data transfer speed—by up to eight times and introduce power-efficiency-maximizing technology that can reduce power consumption by 20% compared with existing levels. We also built intelligent solutions to help rapidly deploy solutions optimized for customers' data centers."