July 20, 2010

Nimbus Goes After HPC Market with Disk-Priced Flash Array

by Michael Feldman

Nimbus Data Systems has unveiled its new high-density enterprise flash memory system, delivering 10 terabytes of solid state capacity per 2U shelf. The S1000 can scale up to 250 TB per system and is being priced to challenge spinning disk appliances head on. For HPC and other enterprise users looking to turbo-charge performance of terascale-sized data sets, Nimbus offers a compelling case for making the switch to flash technology.

Four-year old Nimbus is headquartered in San Francisco, Calif., and had been aggressively pursuing the emerging flash-based storage market with its S-class storage arrays. The company has managed to collect about 200 customers, the largest being the US Department of Defense. They’ve also corralled OEM wins with IBM Tivoli and AMCC. As a result, Nimbus says they’re profitable and debt free — not bad for a company that grew up during one of the worst economic downturns in modern times.

The general idea behind employing flash memory for I/O drives is to take advantage of Moore’s Law in order to close the performance gap between external storage and the other computer components. Over the past 10 years, hard drives have not become appreciably faster or more power efficient, while the performance of a computer’s solid state components has increased several-fold. “We believe storage is on an unsustainable trajectory in the datacenter,” says Nimbus CEO Tom Isakovich. “While CPU, memory and network performance have all grown exponentially, storage performance and storage efficiency really have not kept pace.”

External storage demand is escalating, though. Virtualization, data warehousing, and high performance computing are multiplying the need for more I/O, especially random-access I/O. Isakovich says more hard drives, storage tiering, and cache solutions are not the answer. According to him, while they may boost performance a bit, they’re really not addressing the underlying inefficiency of the spinning disk technology. “Drives have really run their course,” says Isakovich.

Nimbus’ mission to drive a stake through the heart of the hard drive was launched in April, with its first all-flash memory S-class storage arrays: the S250 and S500, which provided 2.5 TB and 5.0 TB per shelf, respectively. All of the S-class offerings use Micron’s Enterprise Multi-Level Cell (EMLC) NAND flash, which is five times more durable than vanilla MLC used in consumer devices and much less expensive than Single-Level Cell (SLC) NAND commonly used for most enterprise SSDs. SLC remains the more robust technology, but at about quadruple the cost and a quarter of the density of EMLC silicon.

Nimbus has managed to layer even more reliability on top of the EMLC silicon by incorporating write amplification, wear leveling and dual-parity RAID into its design. They also over-provision the storage by 28 percent to account for the inevitable degradation of the NAND devices over time. The S1000 employs the higher density 34 nm EMLC NAND from Micron, which makes it possible to offer 400 GB of storage per blade. (Because of the over-provisioning, there is actually 512 GB per blade.) The product comes with a one-year warranty, which is upgradeable to three or five years, although Isakovich believes the hardware will actually be just fine for up to 10 years.

Although S1000 performance may be less than the more expensive SLC-based flash memory products out there, the Nimbus offering easily outruns 15K RPM disk array technology typically found in tier 1 storage. Compared to disk, the S-class products deliver up to 24 times more IOPS (1.65 million), up to 16 times faster data transfer (7.2 GB/sec), and 95 percent lower latency (300 microseconds). Space-wise, a single S1000 2U shelf can deliver the same number of IOPS as in four racks of spinning disks.

Since no moving parts are involved, power savings are equally as impressive. Nimbus is claiming 90 percent lower energy usage — as low as 15 watts per terabyte — and a 70 percent reduction in BTU cooling demand. And since there is less heat generated and no motors to wear out, fewer replacements will be needed.

An S1000 shelf is made up of 24 hot-swappable storage blades. Up to 25 shelves can be stacked via 6G SAS ports, making it possible to deploy a 250 GB file system all in flash. A storage shelf is powered by two Intel quad-core Nehalem processors, although Isakovich says expansion shelves don’t require CPUs or the associated memory. According to him, the flash is so much faster than a disk that the CPUs are rarely tied up waiting for I/O to complete, so you just need less of them to manage the storage.

Since all S-class gear speaks iSCSI, NFS, and CIFS, the hardware can act as both a SAN device and a NAS device. Systems come standard with four 10GbE ports (SFP+ or 10GBASE-T) per appliance, which can auto-negotiate down to GbE when needed. Nimbus is also now offering an upgrade to twelve 10GbE ports, using a technology they’re calling “FlexConnect.” It employs triple active-active 10 GbE network controllers, and, in some cases, will eliminate the need for a standalone SAN switch.

The combination of off-the-shelf 10GbE components, Intel CPUs and EMLC NAND chips has enabled Nimbus to achieve cost parity with 15K disks products. All the S-class products, including the new S1000, are priced at $10,000 per terabyte, which is more or less in line with other tier 1 disk-based appliances.

Of course, any vendor could assemble similar hardware, but the S1000 is more than just flash-in-a-box. The real secret sauce is Nimbus’ HALO operating system, a full-featured software stack that comes standard in all S-class platforms. It includes snapshots, replication, mirroring, deduplication, compression, thin provisioning, real-time analytics, proactive notification, and a Web management interface. In late 2010, the company is planning to make a programmable API available as well. Because all this functionality is baked in, there is no need to purchase third-party software or hardware to make the system enterprise-capable. “We think that gives us a sustainable advantage since it has taken us five years to write all this software,” says Isakovich.

Because the company has been able to solve the acquisition cost penalty for flash, while at the same time offering a feature-rich enterprise storage platform, it may be carving a unique home for itself in the IT landscape. Competitors like NetApp, EqualLogic (Dell) and EMC all offer SSD capabilities to one extent or another, but there are no pure flash offerings to match the Nimbus S-class. On the other hand, pure flash array vendors may offer better performance with SLC NAND, but typically bundle little if any software with their systems. And because those systems are based on the more expensive SLC technology, they come at a price premium.

With the S-class platform, Nimbus is looking to go after IOPS-critical storage applications, especially virtualization, traditional database processing, and On-Line Transaction Processing (OLTP). Now, with the higher capacity S1000, they have a credible entry for the HPC market. Data-intensive applications like seismic analysis, image rendering, and many science codes are I/O bound and thus ideally suited for flash-based storage. Isakovich says they have a proof of concept deployment at one of the big supercomputing centers and also have a couple of oil and gas companies looking at systems. He expects to see some customer deployments by the end of the quarter.

The new platform currently tops out at 250 TB per system, but the dedupe and compression technology can boost the effective storage by a factor of 3 to 10, pushing the S1000 into the petascale realm. According to Isakovich, they’re planning to expand system capacity even further later this year. “The demand we’re seeing from the HPC community is rather significant and we think we can continue to push the density envelope even more,” he says.

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