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Nonvolatile memory vendor AgigA Tech Inc. is sampling a DDR4 NVDIMM module that shifts data from dynamic RAM (DRAM) to NAND flash for persistent memory channel storage.
AgigA Tech's DDR4 nonvolatile DIMM technology combines standard DRAM and nonvolatile multilevel cell (MLC) or single-level cell (SLC) NAND flash memory, an onboard flash controller, and a privately labeled super-capacitor in place of battery backup. AgigA Tech, a subsidiary of Cypress Semiconductor Corp., brands its DRAM-NAND memory configuration as Agigaram, and plans to go to market with server manufacturers and secondary storage vendors.
NVDIMM is a form of nonvolatile DRAM that plugs into a dual inline server slot. The vendor's DDR4 Agigaram supports DRAM storage capacities up to 16 GB, a fourfold increase from the 4 GB maximum of the DDR3 iteration, which has been shipping for two years.
Jeff Chang, vice president of marketing and business development at AgigA Tech, based in San Jose, Calif., said the new DRAM modules are based on DDR4 industry standards published in 2012 by the JEDEC Solid State Technology Association. DDR3 and earlier iterations required server vendors to develop special hardware hooks, BIOS code and drivers.
"The idea [of DDR4 standards] is that you'll be able to buy any standard off-the-shelf server platform and NVDIMMs will be plug-and-play," Chang said.
JEDEC standards define two hybrid NVDIMM modules. NVDIMM-N modules -- the type made by AgigA Tech -- are designed with standard DRAM and flash for backup and restores. NVDIMM-F modules directly access NAND flash as a block-based storage device.
Jeff Changvice president of marketing and business development, AgigA Tech
NVDIMM-N has seen decent adoption in storage arrays because it can be used to replace battery-backed DRAM, "which works well, but causes system administrators [to have] sleepless nights, since batteries are not all that reliable," said James Handy, a principal analyst at Objective Analysis, based in Los Gatos, Calif.
AgigA Tech NVDIMM modules trade capacity for DRAM-like latency and target different use cases than that of memory channel storage pioneer Diablo Technologies Inc., which in August released its DDR4 Memory1 all-flash product, with up to 256 GB of system memory per module.
Chang named Huawei Technologies Co. Ltd. and Nimble Storage as early design wins. Nimble integrates AgigA Tech's DDR3 memory channel storage as a write cache in its proprietary Cache Accelerated Sequential Layout (CASL) file-system architecture for CS Series hybrid arrays.
"We gear ourselves as a complement to a superfast tier of solid-state storage," Chang said. "We can store super-hot data or metadata in NVDIMMs and get DRAM access latency."
Greg Wong, founder and principal analyst at Forward Insights in North York, Ontario, said AgigA Tech's use of nonvolatile RAM and capacitors enables protection of data in flight.
"When you put data in DRAM and the server goes down, the data in DRAM is lost," Wong said. "What they do is use NAND to back up DRAM and super-caps to hold the power in DRAM. That gives just enough juice to the DRAM, so information can be transferred to NAND. Once it's in NAND, it stays there whenever the system starts back up."
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