August 14, 2012

Startup Aims to Upend Enterprise Storage with MLC Flash-Based Systems

Michael Feldman

Silicon Valley startup Skyera has unveiled a solid state storage system that the company believes will be a game changer for enterprise storage. The product, known as Skyhawk, will use consumer-grade multi-level cell (MLC) flash memory as the basis for a bulk storage solution at a price point of less than $3 per gigabyte. As such, it is designed to compete head-to-head against hard disk-based storage, while offering the superior performance, density and energy efficiency of flash memory.

Although solid state enterprise storage is growing rapidly, it still represents just a small fraction of the $32 billion storage market, mainly because it can’t compete on a cost-capacity basis with spinning disks. The current flash-based solutions today tend to be used as tier 0 storage caches or for data-bound applications where the higher IOPS warrants more expensive capacity. Skyera wants to change that dynamic by employing the cheapest flash in the industry — consumer MLC NAND — and go after the heart of the market. “We are going to challenge the status quo of enterprise storage,” says Skyera’s marketing VP, Tony Barbagallo.

The driving force and behind Skyera is CEO Radoslav Danilak, whose resume includes the founding of SandForce, a flash controller startup that was subsequently sold to LSI for $370 million. He also did a stint at NVIDIA as a chip architect on the Tesla GPU products. Danilak, along with SandForce alum Rod Mullendore, founded Skyera in 2010, with the mission to bring next-generation flash-based systems to the enterprise.

Also on the team are industry veterans Ken Takeuchi (NAND flash designer at Toshiba), Frankie Roohparvar (flash development exec at Micron), Dave Martin (CEO Hitachi Data Systems), Alessandro Fin (product development PNY, SMART Modular Technologies), Roy D Cruz (networking and storage architect Cisco, Brocade, Andiamo), and Dave Ferretti (sales exec at Zetta, StoredIQ, EVault).

That diversity of talent (chip development, storage system design, and networking expertise) was brought together to build Skyhawk. In a nutshell, the new offering wraps a series of “life amplification” technologies around consumer-grade MLC flash so that it behaves more like reliable enterprise-grade SLC (single-level cell) flash. . The company is claiming a Skyhawk setup will be able to deliver a complete SAN system at under $3 per gigabyte and under a $1 per gigabyte with compression and deduplication. That would provide price parity with the HDD-based bulk storage solutions.

Building a general-purpose flash-based system as inexpensive as one using high-capacity SATA drives has never been done before. The most critical challenge for flash in the datacenter is its limited lifetime, especially in regard to writing data. SLC technology can support about 100,000 writes for a given bit before a failure can be expected. That’s is about 50 times as many writes as can be coaxed from consumer MLC. Unfortunately, SLC costs two to three times as much, which means customers pay a significant premium for the extra reliability.

Enterprise MLC (eMLC) is basically a compromise between the SLC and MLC and has been adopted by a number of SSD and flash storage vendors. These companies bring eMLC up to SLC-level robustness by layering on extra flash controller smarts that optimizes write behavior (ECC, wear leveling, caching, etc.). But neither SLC or eMLC can provide the basis for a cost-competitive solution for hard disk storage.

So Skyera went one step further and chose vanilla MLC for their solution. But to give MLC-based storage the 5-year lifespan required for enterprise duty, a number of technologies had to be included to compensate for its natural lack of robustness. “There is no single magic bullet to do that,” Danilak told HPCwire.

First, Skyera built an industrial-strength flash controller that employs adaptive ECC algorithms (patent-pending) to correct for errant bits and optimizes write behavior at the chip level to significantly reduce oxide wear on the NAND devices. Further, they invented a proprietary RAID technology to protect the data in such a way that minimizes extra writes. Finally, the engineers added in-line compression and deduplication to further reduce the write (and read) load on the flash chips. According to Danilak, in aggregate they were able to increase the lifetime of the underlying MLC flash a 100-fold, which allowed them to reach their 5-year usage goal.

Performance is rated at up to a million IOPS per node, which is 25 times better than that of a spinning disk. In general MLC performance is inferior to SLC, but Danilak maintains the difference is less than usually thought, and since Skyera does write optimization, error correction, and compression/dedupe all in hardware, they don’t lose as much performance as a solution that relies on a software assist. In any case, even cheap flash is going to be a lot faster than a spinning disk.

And because Skyera is using the latest 19/20nm MLC technology, their solution is extra dense. A Skyhawk box is able to house up to 44 TB of usable storage (48 TB actual) into a half-depth 1U form factor. That’s probably the densest flash-based storage enclosure on the market and more than 100 times as compact as an HDD system of similar capacity, even using the latest 3TB SATA drives.

To live up to its enterprise-ready credentials, Skyhawk incorporates a software stack expected of typical SAN systems, including snapshots, clones, storage QoS, multi-path support, consistency groups, performance monitoring, LUN management, thin provisioning, and dynamic resizing.

Skyera also integrates internal networking to relieve the communication bottleneck caused by the high bandwidth flash. A Skyhawk box is equipped with 40 Gigabit Ethernet and three 10GbE ports that can hook the storage directly to servers or to intermediate Ethernet switches.

For its initial debut, Skyhawk will come in three configurations 12TB ($48,000), 22 TB ($77,000) and 44TB ($131,000). If the customer chooses to buy the extra capacity enabled by the compression/dedupe feature, disk capacity can be more than doubled. For example, the 44TB configuration becomes a 100TB box. The compression and deduplication processing is actually always turned on since it’s used to extend the lifetime of the MLC flash, but Skyera will charge a 20 to 30 percent premium over the base price if the customer wants to access the extra capacity.

As long as the application needs those extra terabytes, paying that premium is a no-brainer, since it can drive the cost per gigabyte down below a $1. But some customers might get a little tweaked that they’re essentially paying for the same feature twice.

Although Skyhawk has the potential to become a breakthrough bulk storage product, a handful of other vendors are offering MLC-based solutions, including STEC, SMART Storage Systems and Pure Storage. Like Skyera, they are using a variety of error correction and write optimization schemes to improve the usable lifetime of the flash storage. From Danilak’s perspective, he thinks Skyera has the edge until his competitors “figure out how to get write amplification technology like we have.”

General availability for Skyhawk is planned for the first quarter of 2013, but for select customers, the company has an early access program that will make systems available in Q3 2012. And if you’re really eager to see one in action, Skyera will be demonstrating Skyhawk next week at the Flash Memory Summit in Santa Clara, California.

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