Ultrastar SAS Series
Scale with Confidence

Western Digital Ultrastar SAS Series

Generations of Proven Designs Provide Reliable, Secure Data Center Scalability

In the zettabyte age, data centers and enterprises must manage the growing abundance and availability of data. Western Digital delivers a portfolio of dual-port 12 Gb/s Serial Attached SCSI (SAS) SSDs with capacity, performance, and endurance options to help address the challenges of data access. Ultrastar® DC SS540, Western Digital’s 6th generation of SAS SSD drive, delivers exceptional performance to data centers with 96-Layer 3D NAND technology and a proven track record of reliability. Our Ultrastar SAS series includes multiple endurance options to meet the requirements of a full range of applications and workloads. Data security features include self-encrypting drives based on TCG enterprise standards and FIPS validation. Ultrastar SAS SSDs leverage decades of proven enterprise storage expertise in SAS design, reliability, firmware, customer qualification, and system integration to provide end-to-end data protection storage for data centers. Trusted by major OEMs, Ultrastar builds on its strong tradition of leading-edge SAS SSD drives to deliver bigger capacity and higher performance, combined with a continued emphasis on reliability to create global scalable, high-availability servers, and storage systems where data can thrive.


    • Capacities from 400GB to 15.36TB
    • Reliable, proven dual port 12 Gb/s SAS interface supports high-availability storage environments
    • 3D TLC NAND Flash delivers performance and endurance
    • Multiple endurance options support range of data center workloads
    • Enterprise-class 2.5M hour MTBF reliability rating

Applications and Workload

    • Enterprise-class servers and high performance computing
    • Online Transaction Processing (OLTP)
    • Financial Transaction Systems
    • File Servers
    • Database Analytics.
    • Space and/or power-constrained environments
Ultrastar DC SS540

Ultrastar DC SS540





Form Factor


Endurance (Drives writes per day, DW/D)

Maximum Terabytes Written (TBW)


Flash Memory Technology


Sequential Write (max MiB/s, 128KiB)

Random Read (max IOPS, 4KiB)

Random Write (max IOPS, 4KiB)

Mixed Random Read/Write (max IOPS 70%R/30%W, 4KiB)

Read/Write Latency (μs, max)


Unrecoverable Bit Error Rate (UBER)

MTBF (M hours)

Annualized Failure Rate (AFR)

Availability (hrs/day x days/week)

Limited Warranty



Operating (W, typical)

Idle (W, average)

Physical Size

z-height (mm)

Dimensions (width x depth, mm)

Weight (g, max)

Ultrastar DC SS540



SAS 12 Gb/s

SFF 2.5-inch drive

3 DW/D: 6.4TB / 3.2TB / 1.6TB / 800GB / 400GB
1 DW/D: 15.36TB / 7.68TB / 3.84TB / 1.92TB / 960GB / 480GB


3 DW/D: 36,170 / 17,520 / 9,410 / 4,700 / 2,350
1 DW/D: 30,110 / 15,050 / 6,790 / 3,760 / 1,880 / 940





3 DW/D: 240,000
1 DW/D: 110,000

3 DW/D: 300,000
1 DW/D: 200,000

3 DW/D: 150/80
1 DW/D: 150/300


1 in 1017




5 years


+5 VDC, +12 VDC

9, 11, 14

<15TB: 3.7W, >15TB: 4.7W



70.1 x 100.45