NetApp has tested Seagate-made heat-assisted magnetic recording (HAMR) spinning disk hard drives, which are likely to hit the market this year in capacities of 20TB-plus.

HAMR drives overcome limitations of current generation spinning disk drives, which rely on perpendicular magnetic recording. As the name implies, PMR records magnetically at 90 degrees to the platter surface. This can become unstable as recording densities increase.

HAMR, by contrast, uses heat of up to 450 degrees – and rapid cooling – to concentrate its recording into a much smaller area, and this is what allows much greater potential hard drive densities.

It is expected that HAMR-based drives will ship this year, with capacities expected in the 20TB-plus range. Current HDD technology has topped out at drive sizes of around 15TB. Seagate expects HAMR capacities to increase by about 30% per year and to reach 40TB by 2023

So far, Seagate says it has manufactured more than 40,000 HAMR hard drives and started shipping out test batches to storage vendors last year.

NetApp has revealed it has tested Seagate Exos HAMR hard drives and expects to use them in its FAS and E-series storage arrays when they are ready to ship.

But what use can such massive hard drives be put to? Spinning disk hard drives are increasingly being pushed down the performance curve by flash drives, and disk rebuild times for HDDs in single figure TB capacities are already onerous, potentially taking days.

Read more about disk storage There will be more data in the public cloud than enterprise datacentres or consumer devices

The internet of things will have a huge impact on storage – the sheer volume of data

Quite obviously, such drives will be nowhere near “hot” primary production operations. Instead, key use cases are likely to be nearline or cold storage, for data that is some way past the frequent access stage.

In a Seagate blog post, NetApp senior technical director, Tim Emami, said: “Our latest testing indicates HAMR technology has reached the stage that allows it to move to the next level; ie, real application testing.

“We’re investing the time and resources now to unlock the benefits of HAMR’s future capacity growth and requirements. Our next targeted milestone is a limited production customer deployment.”