Driving Up Capacity and Driving Down TCO for Cloud and Hyperscale Data Centers

The breadth and depth of Big Data is driving the universal need for higher capacities across a broad spectrum of applications and workloads. Laying the foundation for a worry-free data center, Western Digital delivers the capacity to conquer the data explosion with the Ultrastar DC HC500 series of hard disk drives (HDDs). The DC HC500 series is designed for public and private cloud environments where storage density and cost-efficient infrastructure is critical.

The 18TB/16TB Ultrastar DC HC550 HDDs are the first commercial implementation of Energy-Assisted Magnetic Recording technology and utilize the industry’s first Triple Stage Actuator. These technologies, integrated with HelioSeal on a 9-disk platform, deliver the highest areal density and unmatched Total Cost of Ownership for customer and market needs.


Solves TCO Challenges

High Capacity

Up to 18TB HDDs, drop-in ready for Big Data workloads

Low Power

Up to 61% lower idle W/TB than 10TB Ultrastar air-filled drives

More Reliable

25% higher MTBF rating than air-filled HDDs


  • Up to 18TB capacity in a standard 3.5-inch form factor
  • Industry’s first Energy-Assisted Magnetic Recording technology
  • Industry’s first Triple Stage Actuator
  • Leading HelioSeal technology
  • Reliable, field-proven design across five generations
  • HelioSeal design delivers power efficiency (Watts/TB)
  • 2.5M hours MTBF rating and a 5-year limited warranty

Applications and Workloads

  • Cloud & Hyperscale Storage
  • Massive Scale-Out (MSO), high-density data centers
  • Distributed File Systems
  • Bulk storage using Object storage solutions like Ceph™ and OpenStack Swift
  • Primary and secondary storage for Apache Hadoop® for Big Data Analytics
  • Surveillance Analytics

Continuous Innovation for Highest Capacities and Lower TCO

The Ultrastar DC HC550 18TB CMR HDD and Ultrastar DC HC650 20TB SMR HDD are delivering industry leading capacity for the data center through a combination of new and proven technologies.

Western Digital is the first to deliver Energy-Assisted Magnetic Recording (EAMR) technology and a Triple Stage Actuator (TSA). These new technologies combined with further mechanical innovations and HelioSeal technology provide the industry’s highest capacities to enable data at scale with optimized TCO for data center architectures, while maintaining workload reliability and performance.


Ultrastar DC HC500 Series
Product Portfolio

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Ultrastar DC HC550

Ultrastar DC HC530

Ultrastar DC HC520

Ultrastar DC HC510


Extreme Capacity

18TB CMR HDD for hyperscale, cloud, and enterprise storage

Areal Density Leadership

Energy-Assisted Magnetic Recording technology, Triple State Actuator and 6th generation product with HelioSeal technology on a 9-disk platform


Cost-optimized configurations for every important capacity point






SATA 6 Gb/s


18TB / 16TB

Format: Sector size (bytes)2

4Kn: 4096
512e: 512


Data buffer (MB)3


Rotational speed (RPM)


Sustained transfer rate
(MiB/s, typical)
(MB/s, typical)4



Error rate (non-recoverable bits read)

1 in 1015

MTBF (M hours, projected)5


Annualized Failure Rate (AFR, projected)


Load/Unload cycles (at 40°C)


Availability (hrs/day x days/wk)


Limited Warranty (yrs)



Idle/Operating (Bels, typical)




+5 VDC, +12VDC

Operating (W)6


Idle (W)7


Power consumption efficiency at Idle


Physical Size

z-height (mm)


Dimensions (width x depth, mm)

101.6 (+/-0.25) x 147

Weight (g, max)


Environmental (Operating)

Ambient temperature

5°C to 60°C

Shock (half-sine wave, 2ms, G)


Vibration-Operating (G RMS, 5 to 500 Hz)

0.67 (XYZ)

Environmental (Non-Operating)

Ambient temperature

-40°C to 70°C

Shock (half-sine wave, G)

250 (2ms)/ 150 (11ms)

Random Vibration (G RMS, 2 to 200 Hz)

1.04 (XYZ)

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One MB is equal to one million bytes, one GB is equal to one billion bytes and one TB equals 1,000GB (one trillion bytes). Actual user capacity may be less due to operating environment.


Advanced Format drive: 4K (4096-byte) physical sectors.


Portion of buffer capacity used for drive firmware.


Based on internal testing; performance may vary depending on host environment, drive capacity and other factors. 1MiB = 1,048,576 bytes (220), 1MB = 1,000,000 bytes (106). 


Projected values. Final MTBF and AFR specifications will be based on a sample population and are estimated by statistical measurements and acceleration algorithms under typical operating conditions, workload 220TB/year and temperature 40C. Derating of MTBF and AFR will occur above these parameters, up to 550TB writes per year and 60°C ambient (65°C device temp). MTBF and AFR ratings do not predict an individual drive’s reliability and do not constitute a warranty.


SATA models: Random RW 50/50 8KB QD=1, SAS models: Random RW 50/50 4KB QD=4.


Idle specification is based on use of Idle_A.

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