If you ever worked in IT, you have heard the acronym RAID. RAID stands for Redundant Array of Independent (some call it Inexpensive) Disks. So, it basically refers to a group of disk logically presented as one or more volumes to the external system – a server, for instance.
The main two reasons to have RAID are Performance and Redundancy. With RAID, you can minimize the access time and increase the throughput of data. RAID also allows one or more disks in the array to fail without losing any data.