RAID Structure

• A variety of disk-organization techniques, collectively called redundant arrays of inexpensive disks (RAIDs) are commonly used to address the performance and reliability issues.
• In the past, RAIDs composed of small, cheap disks were viewed as a cost-effective alternative to large, expensive disks.
• Today, RAIDs are used for their higher reliability and higher data-transfer rate, rather than for economic reasons. Hence, the $I$ in RAID now stands for ``independent'' instead of ``inexpensive''.