Marvell is launching a new line of SSD cache accelerators for enterprise storage arrays that it believes could dramatically reduce the cost of deployment and significantly improve performance. The two new devices, dubbed the DragonFly NVRAM and DragonFly NVCache, are meant to solve the same sorts of problems as the consumer-oriented Corsair Cache Accelerators we've reviewed. but on a far larger scale -- and with a lot more firepower.
You can't swing a dead cat more than six inches these days without slamming into someone's new cloud service. This is partly due to the reckless enthusiasm of marketing departments who've fallen all over themselves to rebrand the exact same products with a fluffy moniker, but it's not all marketing hype. Connecting via the Internet to centralized data repositories may solve certain problems on the customer side of the equation, but it creates a monumental headache for the enterprise. The problem? Storage I/O doesn't scale well. Heat, reliability, and vibration have kept rotational media's maximum speed at 15,000 RPM for years. Managing redundancy, I/O overhead, and prioritizing tasks typically occupies a significant percentage of an enterprise storage array's processing power.
By deploying DragonFly cards as above, the storage workload is dramatically decreased
SSDs are a potential solution to some of these problems, but enterprise-level NAND is extremely expensive. Data centers tend to prefer maximum reliability over price, and single-level cell (SLC) Flash can only store one bit of information per cell. Cost savings are only delivered when manufacturers transition to a smaller process geometry, and Flash faces major scaling problems at 20nm and below. The new DragonFly products directly address these limitations.
Acceleration Where You Need It
Both cards contain 4-8GB of DDR3 (up to 3.2GB/s of throughput), have a PCIe 2.0 x8 interface, and are capable of 4K block read/writes at 220K IOPS. The new devices each contain 32GB of SLC Flash that's backed up by ultracapacitor. An ultracapacitor, also known as an electric double-layer capacitor, is a capacitor on serious steroids. These devices can discharge far more quickly than conventional batteries, occupy less space, and, in this case, provide enough power to back up the entire contents of the DragonFly's RAM to the SLC NAND array.
The difference between the NVRAM and NVCache is that the NVCache is designed to work with consumer-level SSDs. Each card apparently contains two SATA ports (visible at top). The company's literature states:
By shifting IOPS from the NAS/SAN target onto a high-performance host cache directly on the server where applications physically reside, DragonFly creates a unique performance-optimized solution. Through this innovative architecture, DragonFly can deliver high IOPS and low application latency on commodity host servers, allowing longer-term data storage to reside on high-capacity NAS/SAN storage.Marvell claims that its DragonFly software further optimizes SSD performance by pruning overwrites and sequentializing random writes. The software is designed to monitor an SSDs wear leveling and garbage collection and works in concert with these features, and reorders writes to reduce the number of IO requests that are passed to storage. The DDR3 is treated as an L1 cache, with the SSD designated as an L2. The NVCache is compatible with all consumer flash drives and supports both 6Gb/s and 3Gb/s devices using MLC or SLC. Windows Server and various Linux distributions are both supported. Power consumption is listed as less than 14W typical, with a brief recharge surge of 25W if the supercapacitors are recharging.
Solutions like this could quickly find a home in enterprise server rooms for many of the same reasons SSD cache drives are increasingly popular with consumers. The DragonFly family offers all the benefits of SSDs at a significantly lower price point. It allows administrators to utilize existing NAS horsepower for other tasks and could save companies' money by giving them the option to increase the efficiency of current arrays rather than building new data centers to handle expected growth.
NVCache devices reportedly start at $3500 for the 4GB flavor, the price for the NVRAM hasn't been announced yet.