What is RAID?

RAID, which stands for Redundant Array of Independent Disks, is a disk storage system that combines multiple physical disks into one logical unit. It provides the user with several advantages in terms of performance, reliability, and scalability. To give a beginner a well-rounded understanding of RAID technology, here’s a brief overview of some of its most important subtopics:

Origins

The concept of RAID was initially developed in 1987 by a team of University of California, Berkeley researchers. It was designed to protect against the failure of single disk drives, primarily through the use of parity-based data redundancy. Since then, RAID has been implemented into many different types of storage systems and is now one of the most common approaches for disk-based storage.

Applications of RAID

RAID is a hugely popular technology used in both consumer and professional settings. In consumer applications, RAID is typically used to increase the storage capacity of computers and other devices, such as NAS (Network Attached Storage) systems. This provides users with extra space for storing their files without having to buy more physical drives.

In professional environments, RAID is often used to create highly reliable storage solutions for mission-critical applications. For example, it may be used in data centers where companies have large amounts of sensitive data that needs to be protected from potential hardware failure or malicious attacks. It can also provide greater performance than a single drive by allowing multiple drives to read and write data simultaneously.

RAID Levels

RAID 0 (also known as Striping)

RAID 0 splits data across multiple drives, increasing the read and write speed of the storage system.

RAID 1 (also known as Mirroring)

RAID 1 creates an exact copy of all data on a second drive, making it very resilient to drive failure.

RAID 2 (also known as Bit-level Striping with Parity)

RAID 2 stripes data at a bit-level and uses Hamming error correction codes for fault tolerance.

RAID 3 (also known as Byte-level Striping with Parity)

RAID 3 stripes data at the byte level with dedicated parity drives. This allows for single disk failure redundancy while also providing higher transfer rates than other levels.

RAID 4 (also known as Block-level Striping with Parity)

RAID 4 stripes data at the block level, allowing for improved performance through better parallelism and faster rebuilds when compared to RAID 5.

RAID 5 (also known as Block-level Striping with Distributed Parity)

RAID 5 distributes parity blocks across all drives in the array, meaning that any disk can fail without impacting access to the other disks.

RAID 6 (also known as Block-Level Striping with Double Parity)

RAID 6 is similar to RAID 5 but has two sets of parity information stored across multiple drives, making it even more resilient against drive failures.