RAID — which stands for Redundant Array of Inexpensive Disks, or sometimes alternatively Redundant Array of Independent Disks) — is a technology that employs the simultaneous use of two or more hard disk drives to achieve greater levels of performance, reliability, and/or larger data volume sizes.
"RAID" is now used as an umbrella term for computer data storage schemes that can divide and replicate data among multiple hard disk drives. RAID's various designs all involve two key design goals: increased data reliability and increased input/output performance. When several physical disks are set up to use RAID technology, they are said to be in a RAIDoperating system as one single disk. RAID can be set up to serve several different purposes. array. This array distributes data across several disks, but the array is seen by the computer user and
Their are different raid protocols, 1 backs up everything that is done on your computer incase of epic failure of comp. Another one you could say splits up the work between multiple hard drives, and makes it appear as 1 hard drive(2 40 gigs appears as 1 80gig in windows), which is alot faster than sata/ide because the pci/onboard raid controller bus has higher bandwidth potential and like a dual core processor the 2 split the work to make any computer doing anything much faster. I believe their is a 3rd protocol for raid, but i cant remember it.
ID 0
"Striped set without parity" or "Striping". Provides improved performance and additional storage but no fault tolerance. Any disk failure destroys the array, which becomes more likely with more disks in the array. A single disk failure destroys the entire array because when data is written to a RAID 0 drive, the data is broken into fragments. The number of fragments is dictated by the number of disks in the array. The fragments are written to their respective disks simultaneously on the same sector. This allows smaller sections of the entire chunk of data to be read off the drive in parallel, giving this type of arrangement huge bandwidth. RAID 0 does not implement error checking so any error is unrecoverable. More disks in the array means higher bandwidth, but greater risk of data loss.
0+1 is another alternative, though it needs a minimum 4 drives. you get the speed and of raid 0 with the safety of raid 1; with 2 drives worth of total space.
for RAID, it also forces the drives to be as small as the smallest disk you have, so it's best to have identical drives.