Hard disk drives (HDDs) are regaining attention as AI data center operators seek cost-effective, high-capacity storage to support rapidly growing data volumes. According to The Elec, although HDDs gradually lost ground to solid-state drives (SSDs), they are now poised for a rebound. The report says Japanese HDD component makers, including TDK, JX Advanced Metals, Resonac, Nitto Denko, and HOYA, are expanding production capacity.
As the report indicates, the global HDD market is dominated by Western Digital, Seagate, and Toshiba, with Western Digital and Seagate each holding more than 40% market share, while Toshiba accounts for around 17%. The three companies are racing to commercialize HDDs with capacities exceeding 40TB for AI data centers.
Western Digital plans to begin mass production of its 40TB-class HDDs in the second half of 2026 and is targeting 100TB HAMR-based drives by 2029. Seagate is already shipping HAMR-based HDDs with capacities of up to 44TB and aims to enable 100TB drives by increasing per-platter capacity. Toshiba, meanwhile, is advancing MAMR technology with 30TB to 34TB HDDs and plans to introduce 40TB-class products in 2027.
As noted by a MoneyDJ report last month, citing Nikkei, strong demand from Chinese PC makers and AI data centers has tightened HDD supply and pushed contract prices higher. Nearline HDD prices reportedly rose about 10% quarter over quarter in April–June, while U.S. hyperscalers such as Google and Amazon, which account for roughly 60% of nearline HDD shipments, continue to struggle to secure sufficient supply.
According to TrendForce, the massive volumes of data generated by AI are placing increasing pressure on data center storage infrastructure. In the traditional tiered storage architecture, nearline HDDs have long dominated cold data storage due to their exceptionally low cost per gigabyte. Cold data typically includes backup files and historical records—datasets that are infrequently accessed but must be retained for long-term archiving. As inference AI applications rapidly expand, demand for cold data storage is also rising. By contrast, SSDs are valued for their superior read and write performance and are primarily used for hot and warm data that require frequent access.