Storage vendor tries out new RAID technique

The NearStore data storage appliance from Network Appliance Inc. has a new type of RAID storage architecture, said Richard Scurfield, regional director of defense and intelligence sales for the Sunnyvale, Calif., company's federal subsidiary.

RAID, short for redundant array of independent disks, is an assortment of ways to spread data across multiple disks so that if any disk fails, the data can be fully recovered from the others.
The NearStore technique is called double-parity RAID. Network Appliance claims the RAID-DP technique can recover data even if several disks fail at once.

Most RAID techniques work by adding up the number of bits in data blocks across multiple disks, keeping the total on a separate parity disk. If a disk fails, the data can be recovered by subtracting the sum of the remaining bits from the total stored on the parity disk. Double parity uses a second parity disk, which adds up bits diagonally across different rows of data blocks.

NearStore is a low-cost alternative to network-attached storage or to cheaper, though slower, nearline magnetic tape storage, Scurfield said.

NearStore can hold up to 96T at about $7 per gigabyte for basic configurations. Commercial drives with serial ATA disks and the company's own file management system can deliver nearly the same performance and reliability as a full-fledged NAS unit, at a fraction of the cost, said Mark Weber, vice president and general manager of Network Appliance's federal practice.

About the Author

Joab Jackson is the senior technology editor for Government Computer News.

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