Is NVMe’s Endgame Storage Class Memory?
Article By : Gary Hilson
NVMe could drive the SCM adoption that could fuel NVMe Over Fabrics.
TORONTO – The NVM (non-volatile memory) Express (NVMe) specification has come a long way from its inception as a single standard conceived by a working group to an expanding ecosystem of specifications.
The expanding scope of NVMe, including NVMe Over Fabrics (NVMe-oF), means it can benefit a wide array of devices and systems, not just data centers with SSDs (solid state drives), and in the long run, become a critical element to taking advantage of storage class memories (SCMs) other than flash.
Enterprise Strategy Group senior analyst Scott Sinclair doesn’t see many limitations as to where NVMe could find itself. “Given the pervasive need for performance, it is difficult to think of an area where NVMe would not offer value. It is simply a cost equation. As costs continue to decline, NVMe will be leveraged in more places,” he said. “We are only about a year or two away from NVMe simply being the default for flash.”
No matter where it’s used or regardless of the SCM using it, Sinclair said in general the biggest benefit of NVMe is that it enables flash technology to dramatically reduce storage I/O latencies. It is more often used for application acceleration, but also improves workload consolidation. “The real game changer, however, is the number of external storage systems that support NVMe-oF,” he said. “This allows external enterprise storage arrays to offer the low-latency benefits of NVMe.”
The extensions to the NVMe specification over the past few years are also significant, said Sinclair. “Without NVMe-oF, the low-latency benefits would still be trapped in the server.” It enables IT organizations to enjoy the management, consolidation, and feature benefits of external storage systems that also deliver NVMe-level performance, he said.
The NVMe family of specifications has grown over the years, and today there’s a focus on simplifying and clarifying what is considered core to the base specification. (Source: NVM Express)
For the most part, NVMe is synonymous with flash SSDs, but there’s plenty of discussion about how the potential of other SCMs, such as Intel Optane, can be unlocked too, said Sinclair. “NVMe will benefit flash storage, but it will pave the way for storage class memory adoption.” In fact, it’s essential and NVMe-oF will ease that adoption, he said. “The desire to leverage storage class memory will also help fuel NVMe over fabrics adoption.”
NVM Express board member J Metz said many of the new use cases for NVMe are still rather embryonic. “NVMe is a different paradigm for communication between a host and a target. That has been the genesis of a lot of different ideas.” Everyone from the hyperscalers to consumers have started to realize they don’t have to do one-to-one relationships anymore, but many-to-many relationships, he said. “And in some cases, you’ve got companies that are focusing on a new brand of computational storage, which means I can move my computation and my memory to different places in the system. “We’re just in the beginning phases of where that stuff can actually go.”
Caitlin Gordon, vice president of product marketing at Dell EMC, said NVMe is the means to end and that end is SCM — an Optane SSD demands it, otherwise there’s a bottleneck in the protocolling. “You would have had this lightning fast media and not have been able to access it and get the benefits out of it.” She sees NVMe as the 4K video of enterprise storage. “You feel warm and fuzzy if your storage array has NVMe. The chances that you really use it very frequently are probably pretty low.” And like how 4K is starting to have some real content, NVMe is getting to the point where more people need it.
Similarly, organizations that know they can’t fully tap into the potential of NVMe today are investing to future-proof themselves so they’re ready for SCM, said Gordon. “That’s really where you’re going to get the most bang for your buck and really get to that disruptive level of performance increase. It’s buying an architecture that you know is designed to meet your needs well into the future.” This investment protection is particularly true for NVMe-oF, she said, because although the host environments may not be ready for it, if you’re going to upgrade your fiber channel infrastructure, it makes sense to invest in one that’s NVMe-oF ready. “They’re driving purely for that investment protection.”
Dell EMC’s perspective on NVMe comes from an enterprise storage perspective, but NVMe is not limited to the data center. Industrial customers are starting to ponder the benefits, primarily driven by Intel, Micron, and Samsung, said Scott Phillips, vice president of marketing at Virtium, although many don’t yet have the operating systems to support it. But like enterprise storage, the potential is the low latency and eliminating bottlenecks, he said, which can have a tangible, real-world impact in industrial systems. “SATA is still very strong. It’s very compatible, it’s lower powered, it’s got a lot of different form factor support that people enjoy, so SATA is still very strong, and we expect it to be very strong for five years or more.”
The small number of companies in the industrial space that are moving toward NVMe are looking to Virtium for small form factor, entry-level SSDs, said Phillips, and certainly not the performance levels desired in a data center. “A lot of these industrial applications are single threaded or maybe four threads at the same time, they’re definitely not a database type application getting boot storms and lots of things coming in.”
NVMe isn’t limited to the data center; Virtium recently added high-performance NVMe drives in the small-footprint M.2 form factor to its StorFly industrial SSD family. (Source: Virtium)
A smaller form factor and lower performance requirements means reduced power, which in turn limits generation of heat that throttles performance and creates choppy throughput, said Phillips. “Industrial customers don’t like choppy throughput. They like to have a very steady state performance.” Virtium further keeps a heat from throttling the NVMe performance by using industrial-temperature (I-Temp) support that enables drive endurance in environments ranging from -40Cº to 85Cº. “The trick there is if you let NVMe operate at its full speed, it will create enough temperature itself where it’ll start to performance throttle, relatively quickly in some cases.”
That NVMe can be found in a wide variety of applications and systems with so many different companies beyond memory and SoC (system on a chip) companies furthering its development speaks demonstrates that NVMe is more than just an interface for a specific area of hardware. But as it evolves, said Metz, things become organic. “It’s becoming a little bit complicated, or certainly more complicated than it used to be.”
As a result, NVM Express is trying to simplify the specifications, he said. “What we’ve been doing is taking some of the functionality and the feature sets and trying to figure out what constitutes core technology.” There is the base specification and attachments to the base specification. “We’re trying to simplify things so when people need to try to figure out how to do a proper NVMe solution, they can easily go to the base specifications to figure out what they absolutely need to have.”