The trendline doesn’t look good for hard disk drives

Sales of HDDs to non-hyperscale outfits increasingly rare, say analysts

Feature In early May, independent digital storage analyst Thomas Coughlin shared news of falling sales and revenue in the first quarter of 2025, continuing a trend that started in around 2010. Coughlin cites data from that year showing around 600 million annual hard disk shipments.

In 2025 he thinks around 150 million units will make it out of factory doors.

Hyperscale datacenter operators will buy most of them and have become HDD manufacturers' largest customers. The Register understands cloud and social media outfits order giant batches of HDDs and that diskmakers tailor products to their needs.

Sales of hard disks to non-hyperscale businesses are therefore increasingly rare – and when they do buy, they eschew high-performance machines, according to Gartner VP analyst Julia Palmer.

"Buyers in the primary workloads (block storage) market are increasingly focusing on all-flash storage and exploring quad-level cell (QLC) SSDs as a more cost-effective flash option," she told The Register.

"Traditional mission-critical, performance-optimised enterprise-grade HDDs with 10,000 rpm or 15,000 rpm spin speeds are no longer in demand among enterprise buyers and are being replaced by SSD solutions," she added.

While HDD volumes fall, collective annual shipped HDD capacity is rising – so even though fewer machines are made, they collectively contain more gigabytes than last year's larger disk fleet.

That's because most of the HDDs sold today are "nearline storage" devices designed to hold data that's sometimes needed, rather than in frequent demand.

"Nearline HDDs are designed to be used in all grades of servers and external storage systems as cost-effective, but highly reliable data repositories," said Gartner's Palmer.

Enter AI

It's 2025 so no technology escapes the touch of artificial intelligence, which requires users to gather substantial quantities of data to train models or perform Retrieval-Augmented Generation (RAG). The advent of AI has therefore lifted demand for data storage.

AI, however, is not always a transactional workload – plenty of the data it needs is accessed infrequently.

Nearline disk is more than sufficient for the data needed to feed AIs,

Disk-maker Seagate's Australia/New Zealand Country Manager Jeff Park told The Register hard disks now represent a "capacity tier" that enable users to implement "massive storage" – while requiring less energy than solid state disks and also include less embedded carbon dioxide.

Park said Seagate and other diskmakers have also increased the megabytes-per-second hard disks can handle, making them suitable for more roles – including AI inferencing – even if they can't match solid state speeds. Park said some of the innovation that improved hard disk capacity was driven by Seagate's work for hyperscale customers, meaning that while the world's clouds and social media giants are setting agendas for disk development, their demands are relevant to the rest of us.

Catching up with the cool kids

Hard disks also continue to evolve. Seagate's Park told The Register the company has conducted a proof of concept integration of NVMe hard disks working alongside SSDs.

NVMe (nonvolatile memory express) is the protocol that connects SSDs directly to a server's CPU over the Peripheral Component Interconnect Express (PCIe) bus, greatly speeding data transfer speeds. If hard disks can use NVMe, they'll be relevant in more roles.

Gartner's Palmer thinks NVMe hard disks will arrive "in coming years."

However she also feels the 2020s may be the last decade in which hard disks are relevant.

"Nearline HDDs remain the best choice for storing large volumes of non-active data," she said, and should be able to do so "for a long time."

But for some orgs, "long" may mean just four years.

"While flash storage prices continue to decline, a compelling business case to completely replace HDDs with lower-cost flash isn't anticipated until around 2029," she said.

But that short relevance horizon hasn't seen storage array vendors run away from HDDs, because they know nearline storage remains a widespread need and that businesses that don't need SSD speed will continue to find roles for HDDs.

Indeed, when Taiwanese storage vendor Synology, a challenger in the field, introduced new arrays last month it included a model that only uses HDDs alongside an all-flash model. ®