Understanding RAID groups
Redundant Array Of Independent Disks (RAID) is a mechanism to group hard disks to form the foundation for logical units of storage. Logical disk partitions (drives) or LUNs with file systems or RAW LUNs can be hosted on RAID groups. Every RAID group has two main characteristics: performance and fault tolerance. Having said that, it is important to understand that there are different types of RAID groups based on two principles that dictate how the data destined to the disk group will be written, and they are striping and mirroring:
Striping refers to the act of distributing the blocks of data to be written onto all the disks in the RAID group
Mirroring refers to the act of writing identical copies of data to more than one disk
Striping and mirroring form the basis of all the other type of RAID groups that can be created. Although, understanding every possible RAID level is beyond the scope of this book, we will review a few that are commonly used in a modern day...
