SAN JOSE, California — At the Open Compute Project (OCP) Summit today, Kushagra Vaid, general manager for Microsoft’s Azure hardware infrastructure, announced Project Denali. Its purpose is to create a new standard for solid state device (SSD) storage, specifically targeted for cloud-based workloads. Denali is based on a modular architecture, disaggregating two layers of flash storage.
According to Vaid, about 30 percent of global flash storage output is consumed by enterprises and cloud providers, and about 60 percent of that flash output is consumed by the big cloud companies. “It amounts to billions of dollars in annual spend,” said Vaid. “You want to drive every bit of efficiency out of designs. The big problem with the SSD device is that it’s completely monolithic. You can’t take advantage of innovations.”
He said any innovation requires the whole device to undergo testing and verification. The performance of flash devices is different from each supplier. And the devices aren’t nimble. “If there are several workloads that are running, how do you adapt to these different workload parameters but use the same SSD?” he asked. “These SSDs are not designed to be cloud friendly.”
Project Denali defines a new standard for flash storage specifically targeted for cloud-based workloads. Vaid said Microsoft engineers noted how the disaggregation of the networking stack has resulted in so much innovation, and they wanted to do something similar for SSDs.
Denali disaggregates the lower layer, or media management, from the upper layer, or the software-defined data layout. In between there’s the physical block device (pBLK) interface, which is largely what Denali is about. Microsoft worked with CNEX Labs to standardize the SSD firmware interfaces by disaggregating the functionality for software defined data layout and media management.
“Project Denali is a standardization and evolution of Open Channel that defines the roles of SSD versus that of the host in a standard interface,” writes Vaid in a blog post. “Media management, error correction, mapping of bad blocks and other functionality specific to the flash generation stays on the device while the host receives random writes, transmits streams of sequential writes, maintains the address map, and performs garbage collection.”
Microsoft plans to continue working on Project Denali with an array of ecosystem partners, including CNEX Labs, Broadcom, Samsung, Intel, Marvell, Lite-On Storage, and SK Hynix. When the standard is more mature, Microsoft intends to contribute it to the industry.