Originally publish on HPC Wire: Customers are scrambling to buy any available storage as a result of the AI boom and the ensuring run on flash chips used for storage and memory. But what if old-school spinning disk could also play a meaningful role in AI? That’s the message being told by WD (formerly Western Digital), which is doing brisk business selling its HDDs and JBOD enclosures to cloud customers, AI users, and HPC sites.

“We’re doing very well,” says Scott Hamilton, the senior director of product management for marketing and customer experience at WD. “We were seeing growth anyway, but I think that [the flash shortage] is also driving growth. ‘Okay, we can’t get all flash. So can we get HDD.’”

Since its separation from SANdisk became official in February 2025, WD has pivoted its business plan away from flash and toward hard disk drives (HDDs). The company’s product lineup today consists of HDDs that it manufactures, as well as just a bunch of disk (JBOD) storage enclosures that support HDDs and NVMe drives. It sells these JBOD enclosures with NVMe drives from SANdisk, or leaves it up to OEMs, like VDURA, who fill them with whatever flavor of disk they like.

And here’s something you probably didn’t know: WD also manufactures magnetic heads for tape drives. “I always like to mention this little Trivial Pursuit storage question,” Hamilton told HPCwire in a recent interview. “We are the sole manufacturer of tape heads as well.”

WD is one of just three companies that still manufacture HDDs, along with Seagate and Toshiba. The San Jose, California-based company, which sells nearly 90% of its products to cloud customers, enjoyed a 25% increase in sales last quarter, to $3.02 billion. Business is so good for WD during the AI boom that the company ran out of supply to sell for 2026, CEO Irving Tan said in the February earnings call. It’s due to announce its fiscal year 2026 third quarter results next week; analysts are expecting to see a 40% increase in sales.

This wasn’t supposed to happen. Depending on who you listen to in the IT industry, HDDs were supposed to have disappeared by now, along with tape. They’re both too slow compared to flash storage, we’ve been told. They also have more moving parts and they fail more often. Going all flash with storage brings a lot of benefits, not to mention simplicity. It’s just a matter of time before either HDDs or tape–or both–disappear.

That narrative never got off the ground at WD. “There are certain people that they’d like you to drink that Kool-Aid [that spinning disk is going away], but that’s not the case,” Hamilton said.

While flash holds substantial advantages over HDDs and tape, it still can’t match either storage modality in capacity and cost-per-GB. Nobody predicted the current AI boom would exhaust the world’s supply of NAND for flash and memory–let alone slam the CPU market–but here we are. Suddenly, having a tiered storage plan–with the hottest data stored on flash, warm data on HDDs, and cold data stored on tape–looks not only prudent from an economic perspective, but perhaps the only way to actually store all your data (at least until new flash fabs can be built).

This is the mantra that Hamilton is spreading. “Because of the scarcity of storage and components across the board, I think you’re seeing a lot more conversations about tiering,” he said. “If you look at the tape companies, they’re seeing an increase in tape because everybody’s looking for every bit of storage that they can, and then how to tier it and how to optimize it.”

Different stages of AI have different storage requirements. With the current focus on AI inference and the latency involved in pulling up specific pieces of data from KV caches or databases, having a very fast storage connection, such as flash connected via NVMe, is desirable to keep your users from waiting minutes to get a response from AI prompts. WD offers an NVMe-over-fabric array, the OpenFlex Data24 4000 series, that uses flash disks and can address customers KV cache offload requirements.

But during AI training runs, HDDs connected via Ethernet can provide the speed and the capacity necessary to keep the bits flowing and the GPUs busy. “Definitely on the front end of the AI lifecycle…it’s hard for all of your bulk storage to be on flash,” Hamilton said. “And then if you want to protect, whether it’s checkpoints and archival, to do all that on flash is pretty expensive.”

WD currently manufactures one speed of HDD: 7,200 RPM. The days of 10,000 RPM or 15,000 RPM drives are long gone, having been replaced by flash drives. The company today sells the bulk of its HDDs in the 20TB to 30TB range, according to Hamilton, but it’s actively developing a HAMR (Heat-Assisted Magnetic Recording) HDD capacities up to 100TB, which it plans to deliver by 2029.

It’s also developing high-bandwidth technology that enables simultaneous reading and writing from multiple heads on multiple tracks, which it says will deliver up to 2x the bandwidth of conventional HDDs without power penalties. “We already have proof of concepts where we can increase the performance by 2X,” Hamilton said. “And today, from a proof-of-performance, proof-of-concept perspective, we’ve got the know-how and the ability, we’re projecting 8X performance by 2030.”

The company is also developing so-called Dual Pivot Technology, which adds set of independently operating actuators on a separate pivot inside the drive. WD says this approach will deliver up to 2x sequential I/O gain in the drive, thereby allowing it to maintain consistent seek times as the storage capacity increase to 40TB, 60TB, and eventually 100TB. The eventual goal is to close the performance gap with today’s QLC flash drives.

“The whole idea there is the performance per terabyte doesn’t get degraded. It’s at least maintained, if not improved,” Hamilton said. “That allows us to, with high bandwidth drives, to move up a little bit, rather than get squeezed in that [HDD] flight mentality.”

“Spinning disk fights back,” he said.

(Image feature courtesy WD)