What is a RAID Array and why would you want one? (Hint: you have lots of important stuff to store and little tolerance for losing data.)

RAID stands for redundant array of independent disks. RAID Arrays use multiple hard drives that share or replicate data across the individual mechanisms. (The acronym originally stood for redundant array of inexpensive disks, back in the day when big fast hard drives were wickedly expensive. Over time the price of storage has dropped dramatically as the definition morphed and inexpensive grew to be independent.)

Fault-tolerance and data-integrity are the primary advantages of RAID Arrays over large individual drives. (Overall performance is a significant benefit, as well.) When you write data to a RAID, the data is instantly backed up, as it is written to two drives. If one of the drives in a RAID goes south, the data should be secure on its counterpart. In a proper RAID Array, the bad drive can be pulled out and replaced with a new unit, in a procedure known as hot swapping. As the term implies, this is all done while the unit is up and running.

While RAIDs are most often hung off of network servers, they are sometimes connected to individual workstations used for data-intensive tasks, such as high-end image retouching for print work, 3D animation, and video editing. RAID arrays are most commonly connected with FireWire, SCSI or FibreChannel to maximize data access. Units are typically configured to store terabytes of data. Yuh huh … terabytes.

RAID was originally conceived with five levels (1 through 5). Over the years, the specification has grown to encompass new levels, while other levels fell out of favor. (RAID Level O was an oddball, as it merely sought to share data across two drives with no provision for redundancy.)

In the near future, RAID Arrays will be as common in the connected home as the refrigerator is today. With an ever-burgeoning number of big beefy files to store, families will turn to home RAID units to safeguard their digital movies, music, and family memories.