Without much publicity, Western Digital this week announced its first dual actuator hard drive, a 20TB drive designed to offer sequential read/write performance like a SATA SSD.of Ultrastar DC HS760 Drive It aims to improve IOPS performance per terabyte for hyperscale cloud data centers, competing with Seagate’s dual-actuator Exos 2X family of HDDs. Meanwhile, Western Digital’s product is also the company’s latest rollout of his OptiNAND technology.
The Dual Actuator Ultrastar DC HS760 HDD is based on the company’s single actuator Ultrastar DC HC560 drive, which uses nine 2.2TB ePMR (Energy Assisted Perpendicular Magnetic Recording) platters. However, in the case of the HS760, WD added his second actuator to the drive, essentially splitting the drive into two quasi-independent drives, each half his 4.5 platter (9 sides) has more than . Western Digital claims that by doubling the number of independent actuators, the HS760 can double the sequential read/write speed and improve random read/write performance by 1.7x compared to single actuator drives. claim.
The company still has to upload a datasheet for the dual actuator HDD, but we’re looking at a sequential throughput rate of around 582 MB/s. This is interestingly a bit faster than SATA SSDs which max out SATA-III at around 550. MB/s. However, as is often the case with enterprise hard drives, Western Digital uses Serial Attached SCSI (SAS) here, so you can’t plug the drive into his SATA host.
The two actuators inside Western Digital’s Ultrastar DC HS760 HDD operate independently, so the unit functions as two independent Logical Unit Number (LUN) devices, and both logical hard drives are independently addressable. . This means that data centers will need to introduce certain software adjustments (i.e. they are not drop-in compatible with infrastructure designed for single-actuator HDDs). But due to the added complexity in terms of software/configuration, the data center operator is 37% more energy efficient in terms of his IOPS per watt than the two 10 TB as well as the higher performance levels previously mentioned. A high setup is also promised. device. Essentially, the hyperscaler gets a lot of benefit from using his 2 of his current generation 10 TB HDDs, but the product only takes up the space of his 1 drive.
The main advantage of Western Digital’s Ultrastar DC HS760 20TB is that it offers significantly better performance on an IOPS per TB basis compared to a single actuator hard drive of the same capacity. Typical enterprise-grade 3.5-inch HDDs with capacities of 8 TB to 16 TB offer random performance of 6 to 10 IOPS per terabyte. This is enough to guarantee the data center quality of service. But at 20 TB, random performance drops below 5 IOPS per terabyte, so hyperscalers need to deploy various mitigations to ensure these drives meet QoS requirements. .
Such mitigations include implementing command queuing and delay bounded I/O (LBIO) in firmware, using smaller capacity drives, reducing the available capacity per drive, and even advanced caching methods. includes the addition of All of these methods increase initial costs and total cost of ownership. A hyperscaler therefore needs a drive that can physically increase his IOPS performance per terabyte, and dual-actuator HDDs are the natural answer. What’s more, these hard drives also offer sequential read/write speeds twice that of single-actuator HDDs.
As mentioned earlier, Western Digital isn’t the only one offering dual actuator HDDs. But Western Digital’s Ultrastar DC HS760 beats the competition in the form of OptiNAND technology, which combines an integrated iNAND UFS Embedded Flash Drive (EFD) with firmware tweaks. OptiNAND aims to improve HDD capacity, reliability and performance. Western Digital still has to disclose performance numbers for its Ultrastar DC HS760 drives, but it’s at least clear that the 20TB drives offer more capacity than Seagate’s competing Exos 2X18 18TB drives.
Otherwise, Western Digital treats this drive as a limited-use product, as the HS760 is primarily aimed at hyperscalers. For example, the drive is listed on the company’s website, but the public price is not listed and buyers are required to make sales inquiries. As such, the actual unit price of a new drive will vary slightly depending on order volume, agreements between Western Digital and its customers, and other factors.
Western Digital’s Ultrastar DC HS760 HDD is backed by a 5-year warranty with each LUN rated for annual workloads of 500 TB.
