Disk Backup Goes Modular

ExaGrid's unique approach to disk-based backup has a modular twist.

A unique approach to disk-based backup will debut next week from startup ExaGrid Systems Inc., with a modular twist, officials said.

Many vendors sell disk buffers for tape systems, mostly using low-cost Serial ATA drives, as does ExaGrid. But instead of shaping the drives in a traditional array fashion, ExaGrid puts them in 1-terabyte, 1U (1.75-inch) networked appliances, which can update one another when data becomes corrupted, said Chief Technology Officer and founder Dave Therrien.

Each appliance is a NAS (network-attached storage) device with its own processor, running Microsoft Corp.s Windows Storage Server 2003. But because of ExaGrids Linux-based Grid Protected Storage software, users buy only as much storage as they need, Therrien said. The files get metadata tags for tracking purposes as theyre compressed and moved around the grid, said Therrien, in Westboro, Mass.

Better yet, users can install the Grid Protected Storage software on any commodity hardware that meets the specifications, Therrien said.

"What we wanted to do is separate our PACS [picture archiving and communications system] vendor from the storage," said Tom Schultz, chief engineer at Partners HealthCare Systems Inc., in Boston. But, Schultz said, "every time you wanted to change something, you had to run back to your PACS vendors for it. If we buy something from EMC [Corp.] or IBM, or other big-iron companies, we have to keep buying their disk," which only shifts the problem, he said.

Grid Protected Storage

  • Uses commodity hardware
  • Each device backs up its peers
  • Serial ATA drives, 1 terabyte per device
  • Connects in NAS configuration

With ExaGrids system, "weve been testing it now for two or three months. So far, so good," Schultz said. Partners wont be getting rid of its tape systems, nor its EMC Clariion CX400 storage array, he said. However, "spinning disks all over the place is still too costly from an enterprise standpoint," and so ExaGrids undetermined pricing will be a big factor before a sales decision is actually made, he said.

ExaGrids Therrien has had startup success in the past, having worked at HighGround Systems Inc., acquired by Sun Microsystems Inc. in 2001, and at Epoch Systems Inc., acquired by EMC in 1993.

Without the modular approach, other recent startups have similar ideas.

Permabit Inc., of Cambridge, Mass., created the Permeon with a team of developers from the Massachusetts Institute of Technology and vendors such as EMC and Prime Computer Inc. Like ExaGrids Grid Protected Storage system, Permabits Permeon runs on commodity hardware. Future versions include a compliance model and application-specific models, Permabit officials said.