Netlist has extended its NVAult product line-up with the roll-out of its EXPRESSvault EV3 PCI Express 3.0 non-volatile RAM. The EXPRESSvault claims to be a novel storage-class memory tier aimed at server-side caching, scale-out storage, database and distributed file systems and all-flash arrays. It can also be used as both a block storage device or as a persistent memory extension.

Netlist's VP of worldwide sales Christopher Lopes has revealed that the latest product line is a natural extension of its NVDIMM technology based on input from customers, providing an alternative to flash-only options or ULLtraDIMM technology. It's not dependent on the memory bus technology, he said, and can be integrated with both DDR3 and DDR4 hardware.

NVDIMMs are persistent memory modules that reside on the DDR DRAM channel, combining volatile DRAM and non-volatile flash memory. Under normal power conditions, an NVDIMM operates exactly like a regular DRAM module. During a power failure or system crash, it is powered by a supercapacitor pack. The data within the DRAM is transferred to the flash and can be restored to the DRAM when normal conditions resume.

Netlist's EXPRESSvault has an architecture designed so that data in memory is immediately backed up to flash without the need of a UPS or battery technologies. Lopes said customers putting NVDIMMs in their servers were looking to eliminate batteries as they need to be replaced every two years or so. The goal was also to make it agnostic; EXPRESSvault fits into a standard PCIe 3.0 x8 lane slot, so there's no the need for proprietary hardware and extra motherboard space, he said, and it comes with a Linux driver compatible with standard PCIe peripheral command sets.

EXPRESSvault combines DRAM and MLC flash and is available in 4GB, 8GB, and 16GB capacities and is particularly suited for data centre server and storage that integrate IBM POWER or Intel Haswell/Broadwell CPUs and Serial Attached SCSI (SAS) and PCI Express SSD products, Lopes said, and be used for RAM disks, write buffering and metadata.

Other vendors with NVDIMMs on the market include AgigA's AGIGARAM, which combines standard DRAM with NAND flash and an ultracapacitor power source, while Viking's ArxCis NVDIMM can be slotted into servers and RAID controllers as an alternative for battery backed-up memory modules and be paired with SSDs to extend their life and performance.

NVDIMMs are viewed as the early days of computing architectures that combine storage and memory as a single entity. Early last year, the Storage Networking Industry Association (SNIA) created a special interest group to foster the adoption of NVDIMM. The SIG is an open community under the umbrella of its Solid State Storage Initiative. Netlist is one of its initial participating members.

Jim Handy, principal analyst with Objective Analyst, stated that technologies such as Netlist's EXPRESSvault are at least 10 times more expensive than SSDs. "You really have to need it to justify the cost." He said if you're doing mostly writes, it will perform a lot better, so it makes sense for hyperscale applications, as does incorporating it into a SAN environment in case of power loss. Even there's never disruption, it's like buying insurance. "From that perspective, it's cheap."

Long term, Handy said everyone knows DRAM and flash with completely run out of steam, he predicts around 2023, and DRAM will be replaced by something non-volatile, and some organisations area now creating software that use NVDIMMS as a test platform.

By: DocMemory
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