Design and implementation of flash based NVDIMM

Flash based NVDIMM memory is a practical nonvolatile memory technology that can be used to replace DRAM based computer main memory. It is cost effective and readily available than other types of emerging non-volatile memories. NVDIMM memory can be inserted into off-the-shelf computer boards and requires very minimum system modifications. It fits as an ideal transitional memory technology towards the generic storage class memory (SCM) technology in the future. In this paper, we describe the design of Flash based NVDIMM module and its controller architecture. The module layout, design trade offs and implementing results are discussed. Flash based NVDIMM use commodity DRAM memory during normal operations, it backups data from DRAM to Flash during power surge event. NVDIMM requires ultra-capacitors to provide energy during power transitions. The size of ultra-capacitor required for this task is dependent on the module's power consumption as well as data backup speed. We implemented NVDIMM controller design in FPGA. The module can backup 4 gigabyte data in 13 seconds. We also created two types of non-volatile RAMDISK by configuring the NVDIMM controller with DIMM or PCI-E as main interface. Test measurements shown their IOPS performance are much higher than that of hard disk drive.