RAID

RAID stands for Redundant Array of Independent Disks.

This concept was invented by David A. Patterson, Garth A. Gibson, and Randy H. Katz in 1987 for the sake of improving data reliability and performance by using multiple physical disks.

RAID relies on the concept of redundancy: storing multiple copies of data increases the chances that, if one of the copies is damaged, the other copy remains available. Data is distributed across the disks in specific configurations designed to enhance redundancy or speed.

A level in RAID defines a particular configuration for how data is stored and accessed on the disks: we'll talk about RAID levels 0, 1, 2, 3, 4, 5, 6, 10, 50, and DP in these lecture notes.

Each level offers a tradeoff between redundancy, performance, and storage capacity. Understanding these tradeoffs helps in choosing the appropriate RAID configuration for specific use cases.