Global file system lets administrators manage multiple network-attached storage devices
In some ways, network-attached storage devices have become victims of their own success. Not dependent on a server like traditional storage but instead connected directly to an Ethernet network, stand-alone NAS appliances are a quick and cost-effective way to add new file storage capacity wherever and whenever needed.
There is, however, one blemish in this otherwise rosy picture, which is that information technology managers usually have to treat each NAS box they've deployed as an island. That makes management chores more cumbersome as the number of NAS devices grows.
Now, a wave of new NAS products from companies such as Scale8 Inc., Spinnaker Networks Inc. and Zambeel Inc. is sweeping the market — including two products in the past few weeks — and the trend promises to make life easier for storage managers who are hooked on NAS.
Each company has taken a slightly different tack on product configuration and positioning, but what they have in common is some form of a global or distributed file system. This feature helps define what some market analysts call the "next generation" of NAS devices.
It allows IT managers to create one single, scalable pool of storage, known as a file system, that can span multiple NAS boxes, whether they number two or 200. "We can provide a single name space and file system view that can extend over local-, metropolitan- or even wide-area networks," said Jeff Hornung, vice president of marketing and business development at Spinnaker.
With other NAS devices, throughput speed and upward scalability for a single file system are typically limited to the storage capacity and throughput performance of a single appliance. To go beyond that means adding more NAS boxes, which requires building separate file systems and doing more management work. It's not an appealing prospect given the way NAS has taken off.
"NAS boxes have been proliferating like rabbits," said Steve Duplessie, founder and senior analyst at market research firm Enterprise Storage Group Inc. "The next-generation NAS products have the ability to look like one system, no matter how many are deployed. And dealing with one thing is a lot easier than [dealing with] thousands of things."
Besides easing management work, treating multiple devices as one can also boost performance. "The distributed file system enables you to have multiple [NAS devices] look like one file system to the rest of the network," said Robert "Bo" Ewald, chairman and chief executive officer at Scale8. "That improves performance because you can spread transactions across multiple" storage devices.
The new distributed file system is not the only card these vendors are playing. They are also tapping into the trend to use arrays of low-cost Advanced Technology Attachment disks, instead of the Fibre Channel or SCSI disks that are traditionally used for enterprise-class disk systems. Although ATA disks don't quite deliver the throughput speed of the high-end disk drives, they cost a fraction of the price, Duplessie said.
ATA's favorable economics are spurring a rash of new uses for online disk systems, he said. One example is to speed up backup and recovery operations by backing up data to ATA disks first, instead of directly to tape. Another application is to use online ATA disks as a permanent alternative to off-line tape to store data that doesn't change but needs to be accessed fairly regularly. Examples of this so-called reference or fixed content data include engineering designs, satellite images, financial records and research data.
Zambeel was first out of the gate with a next-generation NAS product when it introduced its ATA-based Aztera storage system last summer. Aztera is based on a distributed hardware and file system architecture that scales to hundreds of terabytes while maintaining the manageability of a single system.
The key to the hardware design is a set of dual Gigabit Ethernet switches that handle load balancing, while software like the Zambeel Fluid File System can span multiple physical devices and pool all the storage resources into a single logical unit. An entry-level Aztera system with 7.5 terabytes of capacity starts at about $300,000.
Zambeel also landed one of the first federal customers when the Energy Department's National Energy Research Scientific Computing Center at Lawrence Berkeley National Laboratory bought an Aztera last fall. One of Zambeel's beta participants, the center deployed an Aztera as part of its Parallel Distributed System Facility, a 390-processor Linux cluster used by researchers for algorithm development, simulations and data analysis in physics and nuclear science investigations.
Spinnaker first got into the action last fall with its SpinServer 3300. That initial model uses Fibre Channel disks and is positioned to compete with high-end NAS boxes from Network Appliance Inc. The 3300 uses Spinnaker's SpinFS distributed file system, which among other features enables storage administrators to move data from one appliance to another without interrupting operations or user access to that data. In March, the company introduced a version of the 3300 that uses ATA disks (see box).
Although Spinnaker has no government sales to report yet, Hornung said that the company has evaluation units at three federal agencies that operate high-performance computing systems.
Scale8 debuted its first product in March, when it started shipping its N2200 ATA-based NAS system. Pricing for a base configuration of 6 terabytes starts at $105,000, and a 12-terabyte model starts at $145,000. The company has actually been using an earlier version of the appliance, including the distributed file system, to operate a business that rents storage capacity to customers.
Enterprise Storage Group's Duplessie said that although many NAS vendors still do not offer a global file system for their appliances, they will eventually need to offer such a feature. Network Appliance offers a distributed file solution for its popular NAS boxes via a marketing agreement with NuView Inc., using that company's StorageX software. Network Appliance calls the solution the Virtual File Manager.
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