Disk Redundancy

RAID is a data storage technology that combines multiple disk drive components into a logical unit for the purposes of data redundancy and performance improvement. You would use RAID when you have a lot of important data that you are constantly changing and need to back up often. Data is distributed across the drives in one of several ways, referred to as RAID levels, depending on the specific level of redundancy and performance required. RAID has 3 different classifications. RAID 0 is known as striping. Computer merges the two or more hard drives into one. It's used for speed. One hard drive giving you data is great, but two hard drives giving you data at the same time is twice as good. RAID 1 is mirroring. Computer sends the exact same data down two pathways. Each hard drive is given the same data. It's used for backup. If one hard drive goes down, the second one takes over and computer works fine. RAID 5 is for parity. This is a special one that requires three hard drives. Basically it's a mix between 1 and 0. So it has the speed as well as the backup. It writes data on the hard drives in such a way that if one of them fails, the other two can rebuild the original data on the 3rd one based on the data they already have. Special algorithms are used to do this. It's used for backup and speed at the same time. RAID 0 can be used to improve performance through concurrent access and/or create large logical disks out of multiple physical disks. RAID 1 is