The Western Digital Ultrastar DC SN861 SSD, designed for the demanding needs of hyperscale datacenters and enterprise clients embracing PCIe Gen5 storage, has stirred considerable interest. Initially, Western Digital’s silence regarding the controller sparked speculation about an in-house design. Though, a recent teardown revealed a surprising collaboration.

Instead of an internal solution, the Ultrastar DC SN861 leverages the expertise of Fadu, a South Korean firm specializing in enterprise-grade turnkey SSD solutions. Founded in 2015, Fadu’s technology is now at the heart of Western Digital’s latest offering.

Fadu’s FC5161 Controller: The Driving Force

the Western Digital Ultrastar DC SN861 SSD is built upon Fadu’s FC5161 NVMe 2.0-compliant controller. This controller is a powerhouse, boasting:

• 16 NAND channels supporting an ONFi 5.0 2400 MT/s interface
• Enterprise-grade capabilities:
  • OCP Cloud Spec 2.0
  • SR-IOV
  • Up to 512 name spaces for ZNS support
  • Flexible data placement
  • NVMe-MI 1.2
  • Advanced security
  • Telemetry
  • Power loss protection

These features, according to sources, are not available on other off-the-shelf controllers – or on any previous Western Digital controllers.

Performance and Specifications

The Ultrastar DC SN861 SSD delivers remarkable performance metrics:

• Sequential read speeds: up to 13.7 GB/s
• Sequential write speeds: Up to 7.5 GB/s
• Random 4K read IOPS: Up to 3.3 million
• Random 4K write IOPS: Up to 0.8 million
• Capacities: 1.6 TB to 7.68 TB
• Endurance: One or three drive writes per day (DWPD) over five years
• Form factors: U.2 and E1.S

U.2 vs. E1.S: Tailored for Specific Workloads

While both form factors share a similar technical foundation,Western Digital has optimized each for distinct applications.

• E1.S: Supports FDP (Flexible Data Placement) and performance enhancements specifically for cloud environments.
• U.2: Geared towards high-performance enterprise tasks and emerging applications like AI.

Power Efficiency: A Key Advantage

The Ultrastar DC SN861 stands out with its low idle power consumption of 5W. This is particularly notable for hyperscalers, where even small reductions in power usage can led to ample cost savings.

While the difference with predecessors may be just 1W, hyperscalers deploy thousands of drives and for thier TCO every watt counts.

Industry Analyst

Availability and Pricing

Western Digital’s Ultrastar DC SN861 SSDs are currently available to select customers, including Meta, and other interested parties. Pricing is variable,depending on factors such as order volume.

FAQ

• Q: What is the primary use case for the Ultrastar DC SN861 SSD?
  
  A: Hyperscale datacenters and enterprise environments requiring high-performance storage.
• Q: What controller does the SN861 use?
  
  A: Fadu’s FC5161 NVMe 2.0-compliant controller.
• Q: What are the available form factors?
  
  A: U.2 and E1.S.
• Q: What is the maximum capacity?
  
  A: 7.68 TB.
• Q: Is the SN861 energy efficient?
  
  A: Yes, it features a low idle power consumption of 5W.