Types of RAID. What is a RAID Controller

RAID 0 RAID 1 RAID 5 RAID 10 RAID 6

There are different types of RAID namely RAID-0, RAID-1, RAID 2,3,4,5,6 and sometimes combination .i.e RAID 10 is a combination of RAID 1 and 0. RAID 0 needs minimum of 2 physical disks to function and although the acronym stands for "redundant" there is no redundancy achieved in this level of RAID. In RAID -0 data is striped equally in each disks by the controller so if 1 disk failed we cannot rebuilt it again but because of distribution of data it speeds up the system performance. RAID 1 is for mirroring of data in each of the disks .i.e 100% of data is copied in each disk . so if one disk failed we can still rebuilt it. Performance improvement is not achieved. RAID 2-6 is for parity . They provides redundancy. We can loose up-to 2 disks on RAID 6 and still built them back. RAID 10 is combination of striping and mirroring so we can achieve both improved performance and redundancy at same time. A piece of hardware or software that manages these RAID volumes is called RAID controller.