Hard drives might not direct a fan courtesy they once did, interjection to a vastly softened opening of SSDs. But they still offer most some-more storage during a reduce cost per gigabyte than your customary plain state drive. Western Digital was a initial association to move helium-filled tough drives to market, and a association is doubling down on a record with a introduction of dual new drives, with a 12TB expostulate shipping now and a 14TB entrance in a nearby future.
The 12GB HGST Ultrastar He12 (HGST is a auxiliary of Western Digital) is an eight-platter expostulate that packs 864Gbits/sq. in. and spins during 7200 RPM. It’s accessible in both SATA and SAS, with a limit detonate send rate of 6Gb/s or 12Gb/s depending on a interface (sustained send rate for a expostulate is matching between a dual versions, during 243MiB/s – 255MiB/s). Both drives have a 256MB cache and an 8ms find time for reads (8.6ms for writes). According to Western Digital, this eight-platter pattern packs in a full dual platters above a highest-density atmosphere drives. For that, we can appreciate helium. Because helium is so most reduction unenlightened than air, expostulate platters can be packaged some-more firmly and there’s reduction quivering and attrition to contend with inside a expostulate itself. In theory, Western Digital could use helium drives to spin a smaller series of platters some-more quickly, yet a appearance of SSDs has approaching put an finish to such endeavors. Even if an craving tough expostulate could be spun adult to, say, 25,000 RPM (1.66x faster than a fastest 15K drives), it still wouldn’t reason a candle to a find times or send rates on complicated plain state storage.
There is a disproportion between a 12TB and arriving 14TB drives, however, even yet both are formed on a same eight-platter pattern and rest on helium: The 12TB expostulate uses PMR (perpendicular captivating recording) while a 14TB expostulate will use SMR (shingled captivating recording). SMR can strech aloft areal densities than PMR since a expostulate marks are overlaid on tip of one another, as shown in a picture subsequent (the picture is creatively from a Seagate presentation, yet a judgment relates to all SMR drives). For some-more on SMR and Seagate’s rollouts, see a coverage here and here.
Because there is now an overlie opposite a tracks, a HDD’s write conduct will overwrite some-more than one lane during a same time. This requires a expostulate to review and afterwards rewrite information to mixed marks during once to equivocate erasing critical information, and it slows down altogether expostulate performance. As a result, SMR drives typically aren’t endorsed for consumer use — they’re dictated for craving deployments where their drawbacks are outweighed by a increasing storage capabilities they offer. SMR drives can container adult to 25% some-more information on a same platter as a required PMR drive, so it wouldn’t warn us to see Western Digital hurl a 16TB SMR expostulate during some indicate in a not-too-distant future. There are dual kinds of SMR drives: host-managed and device-managed. Host-managed drives need a handling complement and/or applications to conduct their idiosyncrasies and safeguard that lane rewriting is kept to a minimum, while device-managed drives benefaction to a handling complement like customary tough drives. The arriving Ultrastar He12 14TB is a host-managed device, that creates it a bad fit for consumer hardware.
Seagate and other companies are approaching to deliver their possess 12TB drives in 2017, with 16TB drives approaching in a subsequent few years (our tea leaves are silent on either this points to 2018 or 2019-2020 for new expostulate introductions).
Now read: How do SSDs work?