RAID (Redundant Array of Independent Disks) is a data storage virtualization technology that combines multiple physical disk drive components into one or more logical units for the purposes of data redundancy, performance improvement, or both. RAID works by placing data on multiple disks and allowing input/output (I/O) operations to overlap in a balanced way, improving performance. RAID arrays appear to the operating system as a single logical drive, and the different schemes, or RAID levels, are named by the word "RAID" followed by a number, for example RAID 0 or RAID 1. Each RAID level provides a different balance among the key goals: reliability, availability, performance, and capacity.

RAID provides several benefits, including:

• Data redundancy: RAID provides redundancy, which means that if one disk fails, the data can be recovered from the remaining disks in the array. This makes RAID a reliable storage solution for critical data.

• Improved performance: RAID can improve performance by spreading data across multiple disks. This allows multiple read/write operations to co-occur, which can speed up data access.

• Scalability: RAID can be scaled by adding more disks to the array. This means that storage capacity can be increased without having to replace the entire storage system.

• Cost-effectiveness: Some RAID configurations, such as RAID 0, can be implemented with low-cost hardware. This makes RAID a cost-effective solution for small businesses or home users.

There are several RAID levels, each with its own advantages and disadvantages. Some of the most common RAID levels include:

• RAID 0: Provides disk striping without parity information. Data is written by segment across multiple disks sequentially until the end of the array is reached, and then writing starts at the beginning again. Provides greater logical disk capacity with faster access time on reads (multiple segments read simultaneously). However, RAID-0 provides no data redundancy — if one drive fails, the entire disk array subsystem is unavailable.

• RAID 1: Provides fault tolerance by using disk mirroring (also called shadowing). Each byte of data on a disk is duplicated on another physical drive, providing 100% data redundancy. RAID-1 provides immediate access to data when either the primary or secondary drive fails, but it has the highest cost of all RAID types, since duplicate hardware is required.

• RAID 2: Eliminates the 100% redundancy overhead of RAID-1 by using a powerful error detection and correction code (Hamming), with bits of the data pattern written across multiple disks.

• RAID 3: Similar to RAID-2, but uses a single check disk per group that contains the bit parity of the data disks; data is interleaved across all disks. Because disk reads are performed across ... [[4]](https://www.gartner.com/en/information-technolog...