Dell this week became the first storage vendor to announce storage arrays with lower-cost triple-level cell (TLC)...
Dell has redesigned its SC Series storage area network (SAN) arrays to support solid-state drives (SSDs) that use Samsung Electronics' 3D flash memory.
Dell said it will begin shipping SC Series -- formerly Compellent -- arrays in August in hybrid and all-flash configurations using Samsung 3D Vertical NAND 1.9 TB and 3.8 TB SSDs. The TLC drives will be available across the SC Series portfolio, including Dell's entry-level SCv2000, midrange SC4020 and SC8000 arrays.
A single SC4020, fully populated with 3.8 TB PCIe TLC drives, provides up to 90 TB of raw capacity in 2U of rack space. Up to 3 PB is possible with a fully populated SC8000 array. Existing SC Series customers can add Samsung TLC drives and download version 6.6 of Dell Storage Center array management software at no charge.
Triple-level cell NAND stores three bits of data per each cell of flash memory. It has more storage capacity and lower performance and reliability than multilevel cell (MLC) NAND and single-level cell (SLC) NAND flash, but costs less than MLC and SLC.
Eric Burgener, a research director with IT analyst firm IDC for its storage practice, said TLC-equipped SC arrays have the highest all-flash storage density at up to 45 TB per rack unit.
"They've built a tiering approach for flash to offer something that other vendors with a single tier of flash can't offer. What Dell gives up [is] write performance, but it's not much of tradeoff since you aren't going to want to have very many writes going to TLC anyway," Burgener said.
Auto-tiering storage software, TLC drives lower flash cost per GB
SC Series arrays previously used SLC drives for write-intensive workloads and directed heavy reads to MLC flash. Dell's Data Progression storage tiering software captures incoming writes on high-performance flash and analyzes access patterns to move data to less expensive storage.
Dell claims the price of an all-flash SC4020 with TLC can be as low as $1.66 per GB before deduplication. The TLC drives also come with a five-year warranty.
Travis Vigil, executive director of product management at Dell's enterprise storage division, called TLC "the next logical step" in the vendor's flash strategy.
"A lot of our customers are looking to benefit by adding flash to their storage arrays, many of them for the first time," Vigil said. "By announcing support for TLC drives, we are trying to remove the cost barrier to flash adoption. We think this can be a real inflection point."
SC arrays could be outfitted entirely with TLC flash, although, Vigil said most customers are likely to combine write-intensive MLC SSDs with TLC drives to handle read-intensive data and an optional tier of 7.5K rpm hard disk drives.
Other vendors are expected to follow suit with TLC drives. Most array vendors have been exploring the technology, and all-flash array vendor Kaminario last week hinted it plans to roll out TLC storage products this year.
Burgener said the next step will be for storage vendors to figure out how to use TLC for archiving, backup and disaster recovery.
"I feel pretty strongly that we'll see other vendors introduce all-flash platforms targeted at secondary storage environments over the course of the next 12 months," he said. "And I think we're going to see a heavy utilization of TLC flash in those environments, separate and apart from what Dell is doing."
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