San Jose, Calif. – Dell today rolled out two storage products that people have been waiting for – an all-flash array and primary deduplication – at the Dell Enterprise Forum conference.
Dell optimized its Compellent SAN array for flash by modifying its Data Progression automated tiering features in the 6.4 version of Compellent Storage Center 6.4 array software. Primary storage dedupe and compression is part of the Dell Fluid File System (Fluid FS) 3 that runs on scale-out NAS appliances that give Compellent and Dell's EqualLogic iSCSI SAN arrays unified storage capabilities.
Other major storage array vendors have already laid out their all-flash strategies, although some are not yet shipping their systems.
Unlike IBM, EMC and NetApp, Dell did not add a dedicated all-flash array. It takes the same approach as Hewlett-Packard and Hitachi Data Systems and makes all-flash an option in an existing platform.
Alan Atkinson, the Dell storage VP in charge of Compellent, said he expects more Compellent customers will use flash as a tier in rather than run 100% flash. He said the Storage Center software's optimized tiering will allow customers to use SSDs to beat the performance of 15,000 RPM hard drives at a lower price.
Compellent uses single-level cell (SLC) and multi-level cell (MLC) solid-state drives (SSDs) in tandem. Each 24-drive 2U flash-optimized SC220 enclosure includes six 400 GB SLC drives and six 1.6 TB MLC drives. The other slots can be filled with MLC flash, SLC flash or 7,200 RPM SAS hard drives.
Compellent already supported solid-state drives as a tier in a hybrid array with hard drives, but Atkinson said that was far more expensive than using all hard drives. He said Compellent altered the frequency of its data tiering to take advantage of SLC and MLC SSDs to bring down the cost in the new version. Data writes go to the higher performing SLC drives while the less expensive MLC drives handle reads.
"We've built tiering into the enclosure itself, so all your writes go to the SLC drives," he said. "What we're showing is for a lot of workloads we're cheaper than 15K drives. Instead of using 15K drives and tiering down to 7,200 RPM drives, you can buy enough flash for data intensive applications and tier down to 7,200 drives at the same cost or less. We think a huge amount of our customer base will stop buying 15K drives."
It's impossible to judge Compellent's price claims now because no pricing will be available until the flash-enabled systems ship in the third quarter of the year.
Atkinson said Compellent flash won't be anywhere near as cheap as the $3 per gigabyte that startup Skyera promises, but added that Compellent is a full enterprise array. He said Dell's goal is to make flash the same price or lower than 15,000 RPM hard drives.
Storage analysts said Compellent is trying to use its strength – Data Progression automated tiering – to try to gain an edge in flash. Data Progression was considered a key feature for Compellent long before vendors sold SSDs in enterprise storage arrays.
"Compellent introduced auto-tiering to the world," said Arun Taneja, consulting analyst for the Taneja Group. "Now they can fine-tune it to make use of the extra tiers." He added that Compellent's tiering between SLC and MLC SSDs is unique. "It's the first use I've seen of tiering between the two types of flash," he said.
Randy Kerns, senior strategist at the Evaluator Group, said Compellent's tiering for flash "was easy for them to do because they support so many tiers already" but wondered if using the two types of flash will confuse customer when they are configuring their arrays. It said it might not be clear how much SLC versus MLC will be necessary.
Compellent also added a denser enclosure, the SC280, which holds 84 3.5-inch 4 TB drives for 336 TB of raw capacity in a 5U footprint.
Ocarina primary dedupe finally arrives
Dell customers have been waiting for primary data reduction since Dell acquired data reduction startup Ocarina in 2010. Dell put Ocarina technology in a disk backup target in 2012 but missed its 2011 target ship date for integrating dedupe and compression into primary storage.
Atkinson said FluidFS 3 supports policy-based dedupe and compression part of the base license. FluidFS 3 also supports SMB 2 and NFS 4 NAS protocols and 2 PB in a single namespace. Dell plans to make it available in the fourth quarter of this year, first on the Compellent FS8600 clustered NAS appliance and then on EqualLogic appliances before the end of the year.
"It's good to see it," Taneja said of Dell's primary dedupe. "We've been waiting for Dell to do something with Ocarina for primary storage for two years now."
Cody Bumgardner, chief technology architect at the University of Kentucky, said data reduction was among the upcoming features Dell laid out for him before he purchased Compellent storage two years ago. He said his shop doesn't have a lot of duplicate data, but "the Ocarina compression will probably benefit us."