Hard drives and solid-state drives are increasing in storage capacity. But just how long can this continue, and how big can a single storage device actually get?

Earlier this year, Western Digial unveiled the Ultrastar DC HC550 3.5 inch hard drive, with nine platters, and available in both 16TB and 18TB models. Only months later, Western Digital unveiled the HC650 model, with a storage capacity of 20TB. All three of these models utilise energy-assisted magnetic recording (EAMR), the first commercial implementation of the technology at scale. When the technology was first trailed by WD back in 2017, they claimed that hard drive capacities had the potential to reach 40TB by 2025. Seagate have opted for a process known as heat-assisted magnetic recording (HAMR) to achieve hard drives with larger storage capacities; the Seagate Exos X16, with a 16TB capacity, is now available to buy. Similarly, Toshiba announced the MG08 Series early in 2019, and according to the Japanese electronics giant, it is the largest capacity conventional magnetic recording (CMR) hard drive in the industry.

So clearly, then, mechanical hard disk drive storage capacity shows no sign of halting anytime soon. But what about solid-state drives? SSDs, which just a couple of years ago were typically available in capacities barely exceeding 500GB, are now reaching the terabytes. As NAND flash is going down in price, the cost of SSDs is falling at the same time, meaning a 1TB SSD could now cost you as little as around £100. In 2018, Samsung unveiled the world’s largest capacity SSD, the PM1643, with 30TB of storage packed into a 2.5-inch form factor. Since then, there have been examples of SSDs with even more storage.

But there are trade-offs that come with cramming large amounts of storage into a single device. In data centres that use RAID configurations, the rebuild time for a high-capacity HDD can be long, risking data loss if one or more of the other drives in the array fails.