Micron is saying at the moment their subsequent technology of NVDIMM-N modules combining DDR4 DRAM with NAND flash reminiscence to assist persistent reminiscence utilization fashions. The brand new 32GB modules double the capability of Micron's earlier NVDIMMs and increase the velocity score to DDR4-2933 CL21, quicker than what present server platforms assist.
Micron shouldn’t be new to the Non-Unstable DIMM market: their first DDR3 NVDIMMs predated JEDEC standardization. The brand new 32GB modules have been preceded by 8GB and 16GB DDR4 NVDIMMs. Micron's NVDIMMs are sort N, which means they operate as abnormal ECC DRAM DIMMs however have NAND flash to backup information to within the occasion of an influence loss. That is in distinction to the NVDIMM-F sort that provides pure flash storage. Throughout regular system operation, Micron's NVDIMMs use solely the DRAM. When the system experiences an influence failure or indicators that one is imminent, the module's onboard FPGA-based takes over to handle saving the contents of the DRAM to the module's 64GB of SLC NAND flash. Throughout an influence failure, the module may be powered both by means of a cable to an exterior AGIGA PowerGEM capacitor module, or by battery backup equipped by means of the DIMM slot's 12V pins.
Micron says the commonest use circumstances for his or her NVDIMMs are for high-performance journalling and log storage for databases and filesystems. In these functions, a 2S server will usually be geared up with a complete of about 64GB of NVDIMMs, so the brand new Micron 32GB modules enable these programs to make use of only a single NVDIMM per CPU, leaving extra slots free for conventional RDIMMs. Each working programs and functions want particular assist for persistent reminiscence supplied by NVDIMMs: the OS to deal with restoring saved state after an influence failure, and functions to handle what parts of their reminiscence ought to be allotted from the persistent portion of the general reminiscence pool. This may be addressed both by means of functions utilizing block storage APIs to entry the NVDIMM's reminiscence, or by means of direct reminiscence mapping.
Micron is presently sampling the brand new 32GB NVDIMMs however didn’t state when they are going to be out there in quantity.
Conspicuously absent from Micron's announcement at the moment is any point out of the third form of reminiscence they make: 3D XPoint non-volatile reminiscence. Micron will finally be placing 3D XPoint reminiscence onto DIMMs and into SSDs underneath their QuantX model, however to date they’ve been lagging far behind Intel in saying and delivery particular merchandise. NVDIMMs based mostly on 3D XPoint reminiscence could not match the efficiency of DRAM modules or these NVDIMM-N modules, however they are going to supply greater storage density at a a lot decrease value and with out the trouble of exterior batteries or capacitor banks. Till these are prepared, Micron is sensible to nurture the NVDIMM ecosystem with their DRAM+flash options.