Redundant Array of Independent Disks (RAID)
RAID, or Redundant Array of Independent Disks, is a technology of saving data on a number hard drives which operate together as a single logical unit. The drives could be physical or logical i.e. in the latter case a single drive is split into independent ones via virtualization software. In either case, the very same information is stored on all the drives and the basic advantage of using this type of a setup is that in the event that a drive stops working, the data will remain available on the other ones. Using a RAID also boosts the overall performance because the input and output operations will be spread among several drives. There are several kinds of RAID based on how many hard drives are used, whether writing is carried out on all drives in real time or just on one, and how the information is synchronized between the hard drives – whether it is written in blocks on one drive after another or it is mirrored from one on the others. These factors imply that the error tolerance as well as the performance between the various RAID types can differ.