Western Digital has begun commercial shipments of its 16TB and 18TB helium-filled hard disk drives for servers and cloud datacenters. 

The company’s new HDDs use a new architecture featuring triple-stage actuators (TSA) as well as the company’s first-generation energy-assisted magnetic recording (EAMR) technology. 

Western Digital says that the same set of technologies will be used to make 20TB HDDs in the coming months.

Western Digital HDD

The Western Digital Ultrastar DC HC550 family consists of two models featuring a 16 TB and 18 TB capacity based on the 6th generation HelioSeal platform. 

The key features of the new platform are nine platters (for both SKUs), a new mechanical design featuring arms with a triple-stage actuator to improve read/write accuracy at an increased number of tracks per inch, and new EAMR heads with an electrical current applied to their writers to generate an additional magnetic field and produce a consistent write signal at high areal densities. 

Western Digital calls its EAMR technology energy-assisted perpendicular magnetic recording (ePMR) as it is an evolution of the conventional magnetic recording (CMR) that has been in use for years.

This set of new technologies enabled Western Digital to increase areal density of its Ultrastar DC HC550 18 TB hard drive to 1022 Gbits/inch2. When the company applies shingled magnetic recording (SMR) to its Ultrastar DC HC650 20 TB HDD in the coming months, the density will further increase to 1160 Gbits/inch2.

(Image credit: Western Digital)

Other characteristics of Western Digital’s Ultrastar DC HC550 products are fairly typical for nearline hard drives designed for 24/7 operation at an up to 550 TB/year workload. 

The HDDs are equipped with a 7200-RPM motor that is attached both to bottom and top of the drive for enhanced reliability, a 512 MB cache buffer, and a SATA 6 Gbps or a SAS 12 Gbps interface.

In addition, the devices feature vibration and environmental sensors. The SATA versions consume 5.6 W in idle, whereas SAS models consume 5.8 W in idle (same as the Ultrastar DC HC530), thus decreasing per terabyte power consumption by 21% when compared to 14 TB HDDs.

From performance point of view, the Ultrastar DC HC550 18 TB offers up to a roughly 270 MB/s sustained transfer rate, which makes it one of the fastest hard drives on the market. Meanwhile, its IOPS/TB performance is somewhat lower when compared to previous-generation models, so users of these HDDs will have to mitigate it somehow to ensure their QoS and other requirements.

Operators of hyperscale datacenters will appreciate a massive 29% capacity increase of the Ultrastar DC HC550 TB hard drive versus its 14 TB predecessor. The new HDDs will enable such companies to store up to 4320 TB of data in a single standard rack (240 drives) at the same power. Increasing data storage capacity per square meter and without an increase in power consumption is tremendously important for Western Digital’s hyperscale clients, so expect the company to sell a boatload of new hard drives.

Western Digital’s Ultrastar DC HC550 16TB and 18TB HDDs are already in use by hyperscale and OEM customers like Datto, DDN, and Dropbox. From now on, these hard drives are also available to other available for cloud, large enterprise customers, and other datacenter clients. 

Furthermore, Western Digital also offers WD Gold 16TB and 18TB HDDs that use the same architecture and technologies as their Ultrastar DC HC550 counterparts to system integrators and resellers. Eventually, these drives will be available from retailers like Amazon, meaning it will be possible to install half a dozen of them into a high-end desktop for over 100TB of storage space.

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