Is MLC flash ready for the enterprise?
Israeli startup Anobit said its multi-level cell (MLC) Genesis SSDs can deliver the reliability and performance of single-level cell (SLC) SSDs at a much lower price. MLC flash memory devices store two or more bits in each memory cell, while SLC devices store a single bit of information in each cell. That gives SLC devices lower latency and higher write endurance cycle ratings with a lower density and a higher cost than traditional MLC drives.
But Dror Salee, Anobit's vice president (VP) of marketing, said Genesis SSDs get around traditional MLC endurance limitations by using a proprietary algorithm they call Memory Signal Processing (MSP) while boosting performance with its controller technology. Anobit claims a write endurance rating of more than 50,000 cycles with a 20,000 IOPS random write and 30,000 IOPS random read, and 180 MBps sustained write and 220 MBps sustained read performance. The endurance rating gives Genesis a write endurance of 10 full disk writes per day for five years, or 7.3 PBs for a 400 GB drive with fully random data.
Salee said Genesis SSDs are sampling with storage system OEMs in 200 GB and 400 GB capacities. They have 3 Gbps SATA interfaces with bridges for Fibre Channel (FC) and SAS connectivity. He said they are sampling with several storage array vendors, and he expects one large OEM to begin shipping them in its arrays later this year. That could be EMC Corp., which has said it will have another source along with STEC for its SSDs.
When asked how Genesis would come to market, Salee said "our first market is in disk arrays, such as [EMC] Symmetrix." Anobit also has its U.S. office in Boston, Salee said, to stay close to its potential OEM partners.
Anobit did not release any pricing details for Genesis.
STEC and other vendors are working on enterprise-ready MLC flash, and Jim Handy, SSD analyst at Los Gatos, Calif.-based market research firm Objective Analysis, said it's only a matter of time until MLC drives become mainstream among enterprise SSDs. But he predicts a slower adoption of MLC than on the client (mobile device) side.
"In 2008 everybody said client SSDs could not be built using MLCs, no questions asked," he said. "A year later, more than 50% of client drives that shipped were MLC. The same type of migration is likely to happen in the enterprise, but it will be slower because enterprise consumers are more skittish about the reliability."
Handy said Anobit has achieved its endurance and performance numbers because MSP and its controllers don't treat all flash chips the same.
"MSP looks at a particular flash chip design and evaluates where all the weirdness is in that flash chip, and figures out how to compensate for it," Handy said. "Anobit will look at a Micron chip, for example, and see it differently than other vendors' chips — and even the next generation Micron chip. It sizes up the environment and does error correction accordingly."
Virident Systems envisions virtual SSD SAN
Virident Systems launched the tachIOn PCIe SSD card in 200 GB, 300 GB and 400 GB configurations. The startup is also developing software that VP of product management Shridar Subramanian said will allow the cards to be clustered into a virtual SAN so customers can share data across different servers. Subramanian said the GreenCloud Storage Software will probably be rolled out early in 2012.
Virident Systems claims a sustained 1.3 GBps or 320,000 IOPS read performance and 200,000 IOPS read/write performance. The company said its cards include end-to-end error correction, advanced capacity management, and global wear-leveling to assure durability and consistent performance. The tachIOn cards can also be upgraded in the field, so a spare can be added to a board without data loss.
Subramanian said Virident Systems has cards sampling with Fusion-io partners Dell Inc., Hewlett-Packard Co. and IBM, as well as Cisco Systems Inc. He said Virident's cards are cheaper than other PCIe SSD options because they don't require overprovisioning. He expects tachIOn to be priced at approximately $34 a gigabyte, or $6,800 for a 200 GB version.
Virident Systems' first cards are SLC devices, but Subramanian said he expects to deliver MLC versions when the cost of MLC chips drop later this year.