Earlier this year, Western Digital rolled out its Ultrastar DC SN861 SSDs without revealing the specifics of the controller they were using. This led many to speculate that the tech giant had opted for an in-house solution. However, a recent dive into the drive’s hardware has shed some light on the true source. Instead of their own tech, Western Digital has chosen a controller from the South Korean firm Fadu. Founded in 2015, Fadu is known for delivering high-quality turnkey SSD solutions tailored for the enterprise market.
The Ultrastar DC SN861 SSDs are designed with the needs of performance-driven hyperscale data centers and enterprise clients in mind, particularly those transitioning to PCIe Gen5 storage solutions. According to a detailed breakdown by Storage Review, the drive employs Fadu’s FC5161 controller, which is compliant with NVMe 2.0 standards. This advanced controller boasts 16 NAND channels, employing an ONFi 5.0 2400 MT/s interface. It doesn’t just stop there—it also offers enterprise-grade features such as OCP Cloud Spec 2.0, SR-IOV, support for up to 512 name spaces via ZNS, flexible data placement, NVMe-MI 1.2, advanced security measures, telemetry functions, and power loss protection. None of these were available in previous Western Digital controllers or in other off-the-shelf options.
Performance-wise, the Ultrastar DC SN861 shines with sequential read speeds reaching up to 13.7 GB/s and sequential write speeds up to 7.5 GB/s. It also excels in random performance, delivering up to 3.3 million 4K read IOPS and up to 0.8 million 4K write IOPS. The drives offer a range of capacities from 1.6 TB to 7.68 TB, supporting one or three drive writes per day (DWPD) over a five-year span. Customers can choose between U.2 and E1.S form-factors based on their specific needs.
Though both E1.S and U.2 models of the SN861 share much of their technical underpinnings, Western Digital has optimized these versions for different purposes. The E1.S model provides FDP support and performance tweaks intended for cloud-based environments, while the U.2 variant is crafted for demanding enterprise workloads and cutting-edge applications like AI.
A standout attribute of the Ultrastar DC SN861 is its efficient 5W idle power consumption. In the context of enterprise-grade SSDs, that’s quite frugal—it’s actually a watt lower than its precursor, the SN840. While this seems minor, in a hyperscale setting where thousands of drives are employed, every watt shaved off can significantly influence total cost of ownership (TCO).
The Ultrastar DC SN861 SSDs are currently being offered to select clients such as Meta and other interested buyers. Pricing details are still under wraps, likely contingent on factors like order volume.
Sources: Fadu, Storage Review
