Earlier this year, Western Digital rolled out its new Ultrastar DC SN861 SSDs, but they kept quiet about the specific controller at the heart of these drives. Many naturally assumed it was another in-house creation. Recently, however, a teardown revealed a different story: the company opted for a controller from Fadu, a South Korean firm established in 2015, known for its robust enterprise SSD solutions.
The Ultrastar DC SN861 is specifically designed with high-performance demands in mind, targeting hyperscale datacenters and enterprise clients making the shift to PCIe Gen5 storage. Photos from a Storage Review article shed light on the fact that it uses Fadu’s FC5161 NVMe 2.0-compliant controller. This controller boasts 16 NAND channels, supporting the ONFi 5.0 interface at 2400 MT/s. It brings a host of enterprise-level features to the table, such as OCP Cloud Spec 2.0, SR-IOV, support for up to 512 namespaces for ZNS, flexible data arrangement, NVMe-MI 1.2, and comprehensive security and telemetry options—all topped off with power loss protection. These are capabilities you won’t find on previous Western Digital controllers or other generic controllers.
When it comes to speed, the Ultrastar DC SN861 makes quite an impression with sequential read speeds soaring up to 13.7 GB/s and write speeds reaching 7.5 GB/s. For random performance, it can handle as many as 3.3 million random 4K read IOPS and 0.8 million random 4K write IOPS. It comes in sizes ranging from 1.6 TB to 7.68 TB and offers endurance ratings of one or three drive writes per day over five years. You can get it in either the U.2 or E1.S form factor, each designed with specific uses in mind.
Though the SN861’s U.2 and E1.S variations share a core design, Western Digital has fine-tuned each to meet different demands. The E1.S model features FDP and optimized performance specifically for cloud computing environments, while the U.2 version is intended for high-performance enterprise workloads and new applications like AI.
A standout attribute of the Ultrastar DC SN861 SSD is its 5W idle power consumption, considered impressively low for something in its class—1W lower than its predecessor, the SN840. While a single watt might not seem like a big deal, in hyperscale environments deploying thousands of drives, every watt saved can significantly impact total cost of ownership.
Currently, Western Digital is selling these high-powered SSDs to select big players like Meta, and others interested in taking their data management to the next level. Pricing details are still under wraps and likely depend on order volume and bespoke needs.
