Disk-to-Disk Backup Grabs the Spotlight
The relatively new idea of using groups of low-cost IDE disk drives as a staging area for data center backup jobs got a shot of mainstream credibility recently when two well-known names in the storage industry introduced disk-to-disk storage solutions.
The new systems, the NearStore R100 from Network Appliance Inc. and the DX30 from Quantum Corp., are not meant to replace tape libraries as the preferred long-term archive medium. Instead, the vendors are positioning the new disk arrays as online archive solutions, providing a sort of temporary holding station for data as it migrates between primary, and very pricey, online disk systems and its eventual offline resting place on tape. Although tape libraries retrieve data much more slowly, they cost about one quarter of the price of the new disk systems for equivalent capacity.
One of the many benefits of having a disk-based middle tier is that backup data can be written to it extremely fast, minimizing the disruption to servers. Perhaps more importantly, backup data can be retrieved just as quickly when data on the primary disks is lost or corrupted.
The concept is appealing to Ben Kobler, a computer scientist at NASA's Goddard Space Flight Center. "This would be of great interest to us. Right now all of our data is stored on tape. It's too expensive to try and move it to disk. As disks become less expensive and we start taking advantage of some of these IDE-type drives, keeping more data on disk to improve processing performance becomes much more viable."
IDE, or integrated drive electronics, refers to the garden-variety disk drives that have been shipping in most PCs for the past 15 years. The newest versions of these drives are also called serial ATA or advanced technology attachment, by some vendors. IDE drives cost considerably less than the fibre channel or SCSI disks that are most common in enterprise storage systems.
Like all of Network Appliance's storage systems, the R100 uses RAID technology to protect stored data. Available now, the R100 comes in configurations that scale from 12 terabytes up to 96 terabytes of storage. The 12-terabyte model with software starts at $275,000, scaling up at about 2 cents per megabyte.
Quantum officials say that the DX30, which will initially come in a three-terabyte model, is in the final stages of testing and will be available commercially in the second quarter of 2002. It also uses Serial ATA drives.
Nexsan Technologies and 3Ware Inc. were the first vendors to introduce IDE-based disk arrays about a year ago, but the companies have faced an uphill battle in spreading word about their products benefits.
Tony Prigmore, senior analyst for Enterprise Storage Group, a marketing analysis firm in Milford, Massachusetts, says, "With Network Appliance and Quantum, you clearly have two of the market leaders. When they go to town with their marketing machines, these are going to become mainstream solutions."