Crash and Burn (Bonus Material)

Dec 9, 2008 7:21 PM, By Steve Oppenheimer

           
 

MIRROR, MIRROR

A RAID (Redundant Array of Independent Disks) combines two or more hard drives to produce a device that your computer sees as a single volume. RAIDs are more reliable and offer better read/write performance than most individual drives. A true RAID is an integrated hardware device with a controller that handles the demanding task of distributing the data among the component disks. A software RAID pairs independent drives into a RAID array, and your CPU has to distribute the data.

There are several types of RAIDs, but the two most often used in less expensive consumer drives are RAID 0 and RAID 1. The interest here is in data safety, and that’s the purpose of a RAID 1, in which pairs of mirrored disks redundantly store duplicate data. If one disk fails, you can access the data from the other. More important, because the same data is written simultaneously to both disks, the system can do advanced error checking, better ensuring the data’s integrity. Although a RAID 1 does supply a sort of emergency safety backup, it does not obviate the need for regular routine backup, because something could happen to the entire array. And with two drives, the chances increase that one will fail.

A RAID 0 stripes the data across several disks, producing superior speed and full capacity, which is valuable for multitrack recording. However, this type of RAID does not provide the data safety of a RAID 1; you don’t get the advanced error checking, and if one disk in a RAID 0 fails, all data is lost.

If you need and can afford the best of both worlds, check out RAID 5 and the less common RAID 6, which use more disks to provide both data safety and speed. For more on this subject, see the article at en.wikipedia.org/wiki/RAID.