First off its important to know that RAID stands for either "Redundant Array of Independent Disks", or more commonly "Redundant Array of Inexpensive Disks". Either way you slice it (pun intended) the basic idea of RAID is to combine multiple hard disks to either increase performance or increase redundancy. Before I get started its important to introduce the term LUN. A LUN is a logical disk that consists of raw physical disk space. LUNs are created as a basic part of the storage provisioning process. They are presented across a SAN to a server as a single physical disk. Note that the title of this article is "Raid Levels Explained and Simplified", and when I say Simplified I mean it. I am going to give a brief overview of most of the common RAID levels and then present a weakness and strength.