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.
Next week, Network Appliance 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 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 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, Cloverleaf Communications, Xiotech, ExaGrid Systems, Tsunami Research and Isilon Systems. 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 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 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.