The annual Flash Memory Summit is where vendors reveal to the world the future of storage technology. Many companies announced innovative products and technical advances at last week’s 2017 Flash Memory Summit that give enterprises a good understanding of what to expect from today’s all-flash products today as well as a glimpse into tomorrow’s products. These previews into the next generation of flash products revealed four flash memory trends sure to influence the development of the next generation of all-flash arrays.
Flash Memory Trend #1: Storage class memory is real, and it is really impressive. Storage class memory (SCM) is a term applied to several different technologies that share two important characteristics. Like flash memory, storage class memory is non-volatile. It retains data after the power is shut off. Like DRAM, storage class memory is very low latency and is byte-addressable, meaning it can be talked to like DRAM memory. Together, these characteristics enable greater-than-10x improvements in system and application performance.
Two years ago, Intel and Micron rocked the conference with the announcement of 3D XPoint storage class memory. In the run up to this year’s Flash Memory Summit, Intel announced both consumer and enterprise SSDs based on 3D XPoint technology under the Optane brand. These products are shipping now for $2.50 to $5.00 per GB. Initial capacities are reminiscent of 10K and 15K enterprise hard drives. SCM-based SSDs outperform flash memory SSDs in terms of consistent low latency and high bandwidth.
Other storage class memory technologies also moved out of the lab and into products. Everspin announced 1 Gb MRAM chips, quadrupling the density of last year’s 256 Mb chip. Everspin demonstrated the performance of a single ST-MRAM SSD in a standard desktop PC. The nvNITRO PCIe card achieved a sustained write bandwidth of 5.8 GB/second and nearly 1.5 Million IOPS. Everspin nvNITRO cards are available in 1 GB and 2 GB capacities today, with 16 GB PCIe cards expected by the end of the year.
CROSSBAR announced that it has licensed its ReRAM technology to multiple memory manufacturers. CROSSBAR displayed sample wafers that were produced by two different licensees. Products based on the technology are in development.
DRAM and flash memory will continue to play important roles for the foreseeable future. Nevertheless, each type of SCM enables the greater-than-10x improvements in performance that inspire new system designs. In the near term, storage class memory will be used as a cache, a write buffer, or as a small pool of high performance storage for database transaction logs. In some cases it will also be used as an expanded pool of system memory. SCM may also replace DRAM in many SSDs.
Flash Memory Trend #2: There is still lot of room for innovation in flash memory. Every flash memory manufacturer announced advances in flash memory technology. Manufacturers provided roadmaps showing that flash memory will be the predominant storage technology for years to come.
Samsung’s keynote presenter brandished the 32 TB 2.5” SSD it announced at the conference. This doubled the 16 TB capacity Samsung announced on the same stage just one year ago. Although the presenter was rightly proud of the achievement, the response of the audience was muted, even mild. I hope our response wasn’t discouraging; but frankly, we expected Samsung to pull this off. The presenter reaffirmed our expectations by telling us that Samsung will continue this pace of advancement in NAND flash for at least the next five years.
Flash Memory Trend #3: NVMe and NVMe-oF are important steps on the path to the future. NVMe is the new standard protocol for talking to flash memory and SCM-based storage. It appears that every enterprise vendor is incorporating NVMe into its products. The availability of dual-ported NVMe SSDs from multiple suppliers helped to hasten the transition to NVMe in enterprise storage systems, as will the hot-swap capability for NVMe SSDs announced at the event.
NVMe-over-Fabrics (NVMe-oF) is the new standard for accessing storage across a network. Pure Storage recently announced the all-NVMe FlashArray//X. At FMS, AccelStor announced its second-generation all-NVMe AccelStor NeoSapphire H810 array. E8 Storage and Kaminario also announced NVMe-based arrays.
Micron discussed its Solid Scale scale-out all-flash array with us. Solid Scale is based on Micron’s new NVMe 9200 SSDs and Excelero’s NVMesh software. NVMesh creates a server SAN using the same underlying technology as NVMe-oF. In the case of Solid Scale, the servers are dedicated storage nodes.
Other vendors told us about their forthcoming NVMe and NVMe-oF arrays. In every case, these products will deliver substantial improvements in latency and throughput compared to existing all-flash arrays, and should deliver millions of IOPS.
Flash Memory Trend #4: The future is data centric, not processor centric. Ongoing advances in flash memory and storage class memory are vitally important, yet they introduce new challenges for storage system designers and data center architects. Although NVMe over PCIe can deliver 10x improvements in some storage metrics, PCIe is already a bottleneck that limits overall system performance.
We ultimately need a new data access technology, one that will enable much higher performance. Gen-Z promises to be exactly that. Gen-Z is “an open systems interconnect that enables memory access to data and devices via direct-attached, switched, or fabric topologies. This means Gen-Z will allow any device to communicate with any other device as if it were communicating with its local memory.”
I spent a couple hours with the Gen-Z Consortium folks and came away impressed. The consortium is working to enable a composable infrastructure in which every type of performance resource becomes a virtualized pool that can be allocated to tasks as needed. The technology was ready to be demonstrated in an FPGA-based implementation, but a fire in the exhibit hall prevented access. Instead, we saw a conceptual representation of a Gen-Z based system.
The Gen-Z Consortium is creating an open interconnect technology on top of which participating organizations can innovate. There are already more than 40 participating organizations including Dell EMC, HPE, Huawei, IBM, Broadcom and Mellanox. I found it refreshing to observe staff from HPE (Barry McAuliffe, VP and Secretary of Gen-Z) and Dell EMC (Kurtis Bowman, President of Gen-Z) working together to advance this data centric architecture.
Implications of These Flash Memory Trends for Enterprise IT
Vendors are shipping storage class memory products today, with more to come by the end of the year. Flash memory manufacturers continue to innovate, and will extend the viability of flash memory as a core data center technology for at least another five years. NVMe and NVMe-oF are real today, and are key technologies for the next generation of storage systems.
Enterprise technologists should plan 2017 through 2020 technology refreshes around NVMe and NVMe-oF. Data center architects and application owners should seek 10:1 improvements in performance, and a similar jump in data center efficiency.
Beyond 2020, enterprise technologists should plan their technology refreshes around a composable data centric architecture. Data center architects should track the development of the Gen-Z ecosystem as a possible foundation for their next-generation data centers.