Storage vendors are taking a cue from the server world of grid computing and building modular array systems that can nondisruptively grow processing power along with capacity. In two weeks, Sunnyvale, Calif.-based Network Appliance Inc. plans to come out with upgrades and enhanced features for its Storage Grid architecture, a set of disk arrays and switches that pool processing and storage capacity among network-attached storage (NAS) servers.
Storage suppliers of all sizes are using a variety of technologies and strategies to get grid storage systems into corporate data centers.
IBM Corp. is "heavily invested" in grid storage as part of an overall grid computing strategy that uses virtualization technology to knit together disparate storage, network and server systems, said Tom Hawk, general manager of enterprise storage systems at IBM.
Over the next year, Hewlett-Packard Co. said it will build on its StorageWorks grid products, which aggregate CPU and capacity under a single console view, to address file serving, archiving and storage management.
But despite all the work on such systems so far, "no one has proven to me they've completed the invention of core grid architecture," said Robert Gray, an analyst at IDC in Framingham, Mass.
The most popular systems today are smaller grid storage products that use low-cost parallel or Serial ATA disks and can operate at the block or file level and aggregate RAID controllers and capacity. The arrays load-balance among self-contained storage modules, allowing performance to grow in a linear manner, because each new module brings not only additional capacity but additional CPUs as well, vendors and analysts said.
Smaller vendors hawking grid-style systems include 3PARdata Inc. in Fremont, Calif., Cloverleaf Communications Inc. in Southboro, Mass., Xiotech Corp. in Eden Prairie, Minn., ExaGrid Systems Inc. in Westboro, Mass., Tsunami Research Inc. in St. Louis, and Isilon Systems Inc. in Seattle. Most of the smaller suppliers pitch boxes to small and midsize companies that need low-cost storage networks to replace direct-attached storage environments there.
"The investment wasn't that huge, and I liked the speed of grid storage," said Phil Jache, deputy director of technology at Sports Illustrated magazine in New York, which purchased a NAS server from Isilon this year to consolidate file servers.
Jache said the box, which has a capacity of about 6.5TB, performed flawlessly during this summer's Olympic Games, storing 250,000 photos and delivering them to editors with lightning-fast read/write speeds.
Clustered storage systems from start-up LeftHand Networks Inc. in Boulder, Colo., operate at the block, not file, level by using the iSCSI protocol. By using iSCSI, LeftHand takes advantage of the ubiquitous IP Ethernet networks to back up and restore data to application servers.
Chris Scholik, network services manager at ALSAC/St. Jude Children's Research Hospital in Memphis, said he purchased a 6TB array based on grid computing technology from LeftHand two years ago to consolidate his server infrastructure. He gives the box high marks for ease of use and affordability.
Randy Kerns, an analyst at Evaluator Group Inc. in Greenwood Village, Colo., predicted that grid disk storage will someday meet enterprise requirements.
Other analysts see grids extending beyond the data center and into the WAN, using object-based storage that marries metadata with information that can be instantly retrieved from wherever it's stored.
IDC's Gray said he expects that storage grids will eventually connect heterogeneous arrays across WANs through a single interface.
Vendors Take Different Paths to Grid Storage
While there are significant differences between various grid storage systems, they all perform one task: aggregating CPU processing power, storage capacity and the ability to grow seamlessly.
Vendors are lumping the terms virtualization, clustering and grid together into one technology marketing pile and calling it grid storage.
And while "any of those terms work" to describe grid computing, said Randy Kerns, an analyst at Evaluator Group, true grid storage must address RAID controller and capacity integration issues.
Close to a dozen smaller vendors, such as LeftHand Networks and 3PARdata, take somewhat different paths to reach the same goal. "The big difference between 3PAR and LeftHand is that (3PAR) has storage controllers clustered together and a pool of storage those controllers can access. LeftHand has nodes that contain the storage," Kerns said.
Larger storage vendors, such as Hewlett-Packard, IBM and Network Appliance, are all knitting together more distributed storage-area network (SAN) environments through open standards, common interfaces and virtualization technology that can link uncommon systems.
Network Appliance's grid storage architecture uses disks, filer heads or engines, switches and its Data Ontap operating system to enable serving mixed SAN and NAS workloads.
"(Start-up vendors' grid systems) are microcosm implementations of what is truly the macrocosm challenge most enterprises face," said Tom Hawk, general manager of enterprise storage systems at IBM. "They're nice, simplistic point solutions, but they have to be integrated into an enterprise infrastructure."
Hawk said most IBM customers are tackling grid storage and grid computing from an architectural standpoint in order to better utilize existing systems as IBM looks at information grids in a larger context -- the context of the WAN.
Over the next year, HP will focus on giving its "smart cells" -- all-in-one modules with controllers, storage and software --the ability to serve up block-level data from databases, integrated heterogeneous array controllers and grid-based storage management. -- Computerworld (US)
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