Earlier this year, Western Digital rolled out its Ultrastar DC SN861 SSDs, generating considerable buzz. Initially, the company kept mum about the controller specifics, which led many to speculate that WD had opted for its own proprietary solution. However, a recent teardown revealed a different story—Western Digital is actually leveraging a controller from Fadu, the innovative South Korean company known for its top-tier enterprise SSD tech since 2015.
The Ultrastar DC SN861 SSD is designed with the demands of high-performance hyperscale datacenters and large enterprises in mind, especially now as they shift towards PCIe Gen5 storage solutions. As featured in a Storage Review piece, the SSD runs on Fadu’s FC5161 controller, fully compliant with NVMe 2.0. This powerhouse boasts 16 NAND channels with ONFi 5.0 at 2400 MT/s and packs a punch with a suite of enterprise-focused features like OCP Cloud Spec 2.0, SR-IOV, support for up to 512 ZNS name spaces, flexible data placement, NVMe-MI 1.2, advanced security, telemetry, and power loss protection. These are capabilities you won’t find on run-of-the-mill controllers or even Western Digital’s earlier models.
In terms of performance, the Ultrastar DC SN861 is impressive. It delivers sequential read speeds hitting up to 13.7 GB/s and write speeds reaching 7.5 GB/s. For random operations, you can expect up to a stunning 3.3 million IOPS for 4K reads, and for writes, it handles up to 800,000 IOPS. The drives come in sizes ranging from 1.6 TB to 7.68 TB, with endurance options offering one or three drive writes per day over a five-year span. They’re also available in U.2 and E1.S form factors to suit different needs.
Though similar in design, Western Digital has customized these two form factors for different applications. The E1.S version is optimized with FDP and performance tweaks for cloud environments, while the U.2 model targets demanding enterprise operations and cutting-edge applications like AI.
Western Digital has amplified the Ultrastar DC SN861’s appeal with its substantial features, but there’s one more standout: a remarkably low idle power consumption of just 5W. In the realm of enterprise SSDs, this is notably frugal—1W less than its predecessor, the SN840. While a single watt might seem trivial, for hyperscale deployments running thousands of drives, every watt trimmed contributes significantly to total cost of ownership.
These robust Ultrastar DC SN861 SSDs are now on sale for select customers, including major players like Meta, and open for broader interest. Pricing specifics remain under wraps, but it’ll likely hinge on order volumes.
Sources include Fadu and Storage Review.
