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Solid-state storage technology has added a high-performance tier to traditional disk-based storage arrays to deal with increasingly I/O-sensitive applications, such as databases, virtual desktop infrastructure and cloud computing. The use of NAND flash in solid-state drives (SSDs), blades and PCI Express (PCIe) cards has skyrocketed in the last two years as flash prices have dropped to compete with legacy hard disk drive systems.
But today's solid-state technologies aren't latency-free. SSDs and blades must traverse network connections to deliver their microsecond-capable performance speeds, and PCIe flash cards face contention issues, especially as the network scales to meet ever-increasing data storage needs.
An emerging solid-state infrastructure developed to solve performance and latency problems is memory channel storage. Using standard dual in-line memory module (DIMM) form factors, memory channel storage places flash storage cards directly in the memory channel. It's similar to DRAM, but with hundreds of gigabytes of persistent capacity.
"It is a DDR3 interface module that goes into the system the same exact way and in the same exact place that a normal memory module would go," said Kevin Wagner, vice president of marketing for Ottawa-based Diablo Technologies, one of three vendors that develop memory channel storage.
"The difference is that this is persistent memory. They are not 8 GB [modules], they are not 16 GB [modules] or anything like that. They are 200 GB and 400 GB [modules]."
Diablo's ULLtraDIMM flash modules install with drivers for VMware's vSphere 5.1 and 5.5 server-virtualization hypervisor, and Microsoft Windows and Linux operating systems; appear to the OS and applications as typical storage devices; and are managed the same way. "From a user's standpoint, there's really no difference between this and other storage media other than this will be faster and have lower latency," Wagner said.
Because the storage modules are located in the memory channel, they are able to scale performance much more efficiently than SSDs and PCIe cards. Each additional device acts independently and in parallel with every other module without the contention PCIe cards face.
Will it grow beyond a niche storage technology?
Memory channel storage still has obstacles to overcome before it achieves widespread adoption and is probably years away from entering the mainstream.
Michele Reitz, a senior research analyst for Gartner, says memory channel storage is still a niche market play because of proprietary technology, required system enhancements for use and a limited number of suppliers. "Until we see these obstacles overcome, it will remain niche in ultra-high-performance and low-latency applications that would benefit from the I/O density that these can deliver."
Reitz also said it will take client education on the technology and benefits, as well as OEM adoption and application software innovation for memory channel storage to achieve market success. She estimates it will take up to 24 months to see significant OEM adoption and up to five years for compelling applications.
Diablo has two significant partners so far. The flash storage on Diablo's ULLtraDIMM modules comes from SanDisk Corp., which also handles the sales side. SanDisk and Diablo recently struck an OEM deal with IBM. IBM will rebrand and include the ULLtraDIMM modules as the eXFlash memory channel storage components in its X6 system x and PureSystems servers.
Two other vendors are racing to gain acceptance for memory channel storage. Foothill Ranch, Calif.,-based Viking Technology and Irvine, Calif.,-based Netlist Inc. also design and manufacture logic-based subsystems.
Diablo and Netlist are competing in both market share and technology ownership. In August 2013, Netlist filed suit against Diablo, alleging patent infringement, antitrust violations, trade secret misappropriation and trademark infringement. The case is pending in the U.S. District Court for the Central District of California in Santa Ana, Calif.