Earlier this year, when Western Digital rolled out its Ultrastar DC SN861 SSDs, there was an air of mystery surrounding the controller used in these drives. With no official details from WD, many assumed the controller came from WD’s own lineup. However, a recent teardown has revealed a surprise: the controller is actually manufactured by Fadu, a South Korean firm established in 2015 that focuses on crafting enterprise-level turnkey SSD solutions.
Targeted at the cutting-edge demands of hyperscale datacenters and enterprise clients embracing PCIe Gen5 storage solutions, the Western Digital Ultrastar DC SN861 SSD is built around Fadu’s FC5161 controller, as highlighted in a recent Storage Review piece. This NVMe 2.0-compliant controller boasts 16 NAND channels with ONFi 5.0 2400 MT/s support and offers a suite of high-end features—ranging from OCP Cloud Spec 2.0, SR-IOV, to advanced security measures and telemetry—not typically found on other standard controllers or previous iterations from Western Digital.
Performance-wise, the Ultrastar DC SN861 SSD truly impresses. It delivers sequential read speeds reaching 13.7 GB/s and write speeds peaking at 7.5 GB/s. In terms of random 4K operations, it handles up to 3.3 million read IOPS and up to 0.8 million write IOPS. These drives vary in capacity from 1.6 TB to 7.68 TB, offering one or three drive writes per day (DWPD) over five years, and are available in both U.2 and E1.S formats.
Both versions of the SN861, while technically similar, have been optimized by Western Digital for different applications. The E1.S variant is enhanced for cloud environments with FDP and performance boosts, whereas the U.2 model is designed for high-performance enterprise settings and newer applications such as AI.
One of the standout aspects of the Ultrastar DC SN861 SSD is its energy efficiency—boasting an idle power consumption of just 5W. This is noteworthy, especially in the realm of enterprise-grade SSDs, and is 1W less than its predecessor, the SN840. For hyperscale deployments where thousands of drives are in use, every watt saved contributes significantly to the total cost of ownership.
Currently, the Ultrastar DC SN861 SSDs are available to select major clients like Meta and others who are keen on leveraging their advanced capabilities. Pricing details remain under wraps, as they’ll likely vary based on order volumes and other factors.
Source references: Fadu, Storage Review.
