Redundanssisamalla

Redundanssisamalla, often translated as "redundant array of independent disks" or RAID, is a data storage virtualization technology that combines multiple physical disk drives into one or more logical units for the purposes of data redundancy, performance improvement, or both. RAID levels specify the exact way in which data is distributed across the disks and what kind of redundancy is implemented. Different RAID levels offer varying degrees of fault tolerance, performance, and storage efficiency.

Commonly implemented RAID levels include RAID 0, RAID 1, RAID 5, and RAID 6. RAID 0, also known as striping, enhances performance by splitting data across multiple disks without any redundancy, making it unsuitable for data protection. RAID 1, or mirroring, duplicates data onto at least two disks, providing excellent redundancy but at the cost of using only half the total disk capacity. RAID 5 utilizes block-level striping with parity data distributed across all disks. This offers a good balance of performance, capacity, and redundancy, able to withstand the failure of a single drive. RAID 6 extends this by adding a second, independent parity block, allowing it to tolerate the failure of two drives.

The choice of RAID level depends on the specific requirements for data availability, performance needs, and cost considerations. RAID implementations can be achieved through hardware controllers, which are dedicated cards, or software, where the operating system manages the RAID array. Hardware RAID typically offers better performance and features but is more expensive. Software RAID is a more cost-effective solution but can place a higher load on the system's CPU.