Earlier this year, Western Digital unveiled its Ultrastar DC SN861 SSD series, but they didn’t initially reveal the brains behind these drives, sparking much speculation. Many suspected an in-house controller was driving the SSDs. However, a recent teardown exposed the true source: Western Digital opted for a controller from Fadu, a South Korean company founded in 2015, known for its prowess in creating top-tier SSD solutions for the enterprise sector.
The Western Digital Ultrastar DC SN861 SSD is explicitly designed for hyperscale data centers and enterprise clients keen on adopting PCIe Gen5 storage. According to a Storage Review article that examined the device, it utilizes Fadu’s FC5161 controller which complies with NVMe 2.0 standards. This controller isn’t just any run-of-the-mill component; it offers 16 NAND channels with a slick ONFi 5.0 2400 MT/s interface. Its enterprise-focused features include OCP Cloud Spec 2.0, SR-IOV, up to 512 namespaces for Zone Name Space (ZNS) support, and flexible data placement. Additionally, it boasts NVMe-MI 1.2, advanced security capabilities, comprehensive telemetry, and robust power loss protection—all features that the previous Western Digital controllers lacked.
Performance-wise, the Ultrastar DC SN861 SSD impresses with its capabilities. It hits sequential read speeds peaking at 13.7 GB/s, while sequential write speeds can reach up to 7.5 GB/s. When it comes to random performance, users get up to 3.3 million random 4K read IOPS and up to 0.8 million random 4K write IOPS. Customers can choose between models ranging from 1.6 TB to 7.68 TB, rated for one or three drive writes per day (DWPD) over a span of five years, available in both U.2 and E1.S form factors.
Although both SN861 form factors share similar tech designs, each is fine-tuned for specific uses: the E1.S version caters to cloud environments, benefiting from FDP and performance boosts, while the U.2 variant is crafted for high-performance enterprise activities and is ready to tackle new frontiers like AI.
Western Digital’s Ultrastar DC SN861 SSD is not just a powerhouse; it also brings a remarkable feature in terms of efficiency: its idle power usage stands at 5W, noticeably lower than the enterprise norm and even 1W less than its predecessor, the SN840. For hyperscalers deploying vast numbers of drives, that single watt difference is a big deal in terms of total cost of ownership.
Currently, Western Digital’s Ultrastar DC SN861 SSDs are available for select buyers, including industry giants like Meta. Pricing details remain under wraps and likely fluctuate based on order volumes.
Sources: Fadu, Storage Review
