The demand for and the capacity of HDDs will continue to increase!Latest technologies for nearline HDDs
for data centers and Toshiba’s initiatives
As the amount of information available on the Internet explodes, Enterprise Capacity HDDs for data centers have undergone various technical innovations that help to further increase their storage capacity.
The following describes the latest nearline HDD technologies of Toshiba Electronic Devices & Storage Corporation (“Toshiba”) while providing answers to frequently asked questions and examples of Toshiba’s HDDs.
As represented by the Internet of Things (IoT), the number of devices connected to the Internet and the range of cloud services is increasing.
Accompanying this trend, the amount of data traversing the Internet is growing exponentially, spurring the demand for cost-effective hard disk drive storage capacity.
The ever-increasing demand for Enterprise Capacity HDDs for data centers is dramatically accelerating design innovations to increase their data storage capacity and power efficiency.
High capacity is required for Enterprise Capacity HDDs, also known as nearline HDDs.
CASE : 01
―― How much will the HDD demand increase because of increasingly prevalent cloud services?
What are the technical requirements for HDDs for data centers?
The data generated through cloud services are stored in very large data centers, designed for power-efficiency and optimal storage density.
The total capacity of the nearline HDDs at data centers is expected to increase at approx. 30% per year over the period of 2017 to 2023. As a result, the total capacity will reach approx. 1,200 exabytes (EB) by 2023, four times that of 2017*1.
Accompanying the information explosion, the storage capacity of both Public and Private Cloud data centers is also expected to increase.
Under these circumstances, manufacturers of nearline HDDs are striving to increase the storage capacity of each HDD unit.
Data transfer rates and reliability are important factors for the selection of enterprise HDDs for servers and storage systems whereas storage capacity is always the top priority for nearline HDDs used in Cloud-scale datacenters.
This is because HDDs with higher capacity help reduce the per-bit power consumption and footprint per unit of storage, reducing the total cost of ownership for data centers.
All the manufacturers of nearline HDDs, including Toshiba, are developing technologies to increase their capacity.
*1 Source : Techno System Research, Jan. 2019
Industry’s first 14-TB CMR nearline HDDs
CASE : 02
―― What is Toshiba’s latest nearline HDD?
What kinds of technologies does it incorporate?
In December 2017, Toshiba was the first*2 in the industry to release 14-terabyte (TB)*3 nearline HDDs in a 3.5-inch*4 form factor using the conventional magnetic recording (CMR) technology called the MG07ACA series. In addition, in January 2019 about a year later, Toshiba released the 16TB called the MG08 series.
The MG07ACA series is characterized by several technical features: 1) a helium-sealed mechanical design, 2) an increase in the number of platters to nine, and 3) storage capacity as high as 14 TB achieved using the CMR technology that preserves compatibility with existing Cloud Infrastructure applications and file systems.
To realize 16TB capacity using CMR technology, MG08 series introduced the technology called two-dimensional magnetic recording (TDMR) which is used in addition to helium-filling and nine-platter packing technologies.
*2 Source: Toshiba Electronic Devices & Storage Corporation, as of December 8, 2017.
*3 Definition of capacity: A terabyte (TB) is 1,000,000,000,000 bytes. A computer operating system, however, reports storage capacity using powers of 2 for the definition of 1TB = 240 = 1,099,511,627,776 bytes and therefore shows less storage capacity. Available storage capacity (including examples of various media files) will vary based on file size, formatting, settings, software and operating system and/or pre-installed software applications, or media content. Actual formatted capacity may vary.
*4 "3.5-inch"or 1.8-inch means the form factor of HDDs. They do not indicate drive's physical size.
Helium-filled HDDs provide low power consumption and low acoustic noise.
CASE : 03
―― What are the benefits of filling HDDs with helium?
Are there any concerns about helium leakage?
Being smaller in mass than the air, the helium molecule greatly reduces the aerodynamic drag on the rotating disks and produces less turbulence on the head suspension assemblies that fly just above the disk surfaces.
The reduced buffeting also helps reduce the vibration of head suspension assemblies and the wobbling of disk platters at high rotation per minute (RPM).
This, in turn, helps increase the tracking accuracy and areal density of each disk while also allowing the distance between platters to be reduced.
Furthermore, helium lowers the drag force acting on the spinning platters, making it possible to reduce the power consumption of the spindle motor, and also reduce the heat associated with the operation of the spindle motor.
Obviously, hermetic sealing technology is required to seal helium gas inside the HDD.
Toshiba Group has a history of leadership in developing precision laser welding technology as it develops and manufactures lithium-ion batteries requiring high hermeticity. This precision laser welding technology is used to weld the top cover of the HDD enclosure so as to capture the helium gas securely for the lifetime of the HDD’s operation.
As long as you handle a helium-filled HDD in the same manner as conventional HDDs, there is no worry about helium leakage.
Squeezing in nine platters into the standard HDD form-factor using high-density design and manufacturing technologies
CASE : 04
―― Are nine-platter HDDs more susceptible to vibration?
Are there any handling precautions specific to these HDDs?
Although nine platters are packed in the 14TB and 16TB models, they provide shock resistance equivalent to that of conventional Enterprise Capacity HDDs. Therefore, these models can be utilized in the same manner as the conventional HDDs.
Indeed, it is true that the storage capacity can be increased simply by increasing the number of platters, but advanced high-density design and manufacturing technologies are necessary to improve the precision and reduce the variations of various components, including the actuator assembly with 18 heads.
This is not easy to achieve without compromising shock resistance performance.
Our success was supported by years of experience in the design and manufacturing of small HDDs as represented by Toshiba’s success in pioneering the popular 1.8-inch HDD that was widely used in portable media players for a number of years.
Drawing on the expertise acquired through experience with small HDDs, Toshiba has established the design and manufacturing technologies necessary to assemble thinner components with high precision, helping Toshiba to be the first in the industry to realize nine-platter HDDs.
The increase in the number of platters reduces the need to push the limit for per-platter areal density and therefore helps improve the read/write design margins and accuracy.
In addition, a reduction in the thickness of platters helps reduce the weight and power consumption of HDDs.
The MG07ACA series provides 40% higher capacity than the previous 10-TB seven-platter MG06ACA10T series, but consumes only 4.53 W at Idle, about 40% lower than the MG06ACA10T series with a power consumption of 7.3 W.
The MG07ACA series is also 10% lighter at 720 g than the 770-g MG06ACA10T series.
This weight reduction was made possible by the use of thinner platters that was enabled by helium-filling technology.
The MG07ACA series contains nine platters in a 3.5-inch form factor with a height of only 26.1 mm.
A platter for the MG07ACA series is 0.635 mm thick whereas the one for the seven-platter MG06ACA10T series is 0.8 mm thick.
The heads, connectors, and printed circuit boards of the MG07ACA series, which are also thinner than those of the previous series, are assembled with high precision by leveraging our expertise for the manufacturing of small HDDs.
Two Dimensional Magnetic Recording delivers higher storage capacity
CASE : 05
―― What kind of technology is TDMR?
CMR uses one writer and one reader per head whereas TDMR uses two readers per head to increase the signal-to-noise ratio of the read signal.
As areal density increases, the pitch between magnetic tracks becomes smaller. As the track pitch becomes smaller, adjacent magnetic tracks will tend to “fringe” or interfere with each other, adversely affecting read accuracy.
To mitigate this problem, TDMR uses two readers spanning across adjacent tracks to measure and offset interference between tracks.
TDMR makes it possible to reduce the track pitch and thereby increase the areal density of HDD platters.
Evaluation and adoption of the MG07ACA series is in progress at an increasing number of hyper-scale data centers.
CASE : 06
―― Is the MG07ACA 14-TB nearline HDD series available in production quantities? Is it already in use at any data center?
Since sampling started in December 2017, the MG07ACA nearline HDD series has been valued by many customers because of its high capacity. In July 2018, volume production began for shipments to some data center customers.
The MG07ACA series also received a positive response from Supermicro, which uses the MG07ACA series for its storage servers.
Use of the MG07 series is also in progress at locations requiring stringent reliability such as research institutions and data centers specialized in algorithm development for self-driving vehicles.
The MG08 series will also be shipped in sequesnce.
Aiming to realize 18-TB and 20-TB nearline HDDs: Leading in capacity
CASE : 07
―― Does Toshiba have any plan to release HDDs with even higher capacity?
Our future roadmap includes HDDs with increasingly higher capacity following 16 TB such as 18 TB and 20 TB.
Assisted magnetic recording technologies will be employed, starting with microwave-assisted magnetic recording (MAMR) for the 18-TB and 20-TB generations. And, we are investigating also HAMR for future products. Research on these technologies will continue to further refine their capabilities to support additional advancements of areal density.
It is important to collaborate with head element and platter manufacturers to develop these new technologies necessary to increase the HDD capacity.
Toshiba’s HDD factory is located in the Philippines where not only Toshiba’s engineers but also those from TDK Corporation, a head element manufacturer, and Showa Denko K.K., a platter manufacturer, are also assembled to facilitate close collaboration and accelerate the development of new technologies. Toshiba will lead the industry in increasing the capacity of nearline HDDs together with its partners.
Productization of SMR nearline HDDs
CASE : 08
―― Shingled magnetic recording (SMR) technology has appeared as an effective means of increasing the capacity of nearline HDDs.
Does Toshiba have any plan to release SMR nearline HDDs?
As SMR writes a new track, it overlaps part of the previously written track in a way akin to roof shingles that partially overlap each other. This means that previously written data cannot be overwritten “in place” and that any updates to previous writes must be recorded as a “new write”.
Although the rewriting operation of an SMR HDD is complicated and may require host-system modifications, SMR HDDs are expected to be widely used for sequential write and read oriented applications that benefit from their ability to record sequentially written data at a higher density than CMR HDDs.
Accompanying the ongoing retrofitting of host systems at some data centers, SMR HDDs are expected to enter widespread use Cloud-scale data centers in 2019 and thereafter.
Toshiba is developing SMR HDDs in parallel with CMR HDDs. Toshiba is planning to release SMR HDDs in a timely manner according to their prevalence in Cloud-scale data center architectures.