RAIDjärjestelmän

RAIDjärjestelmän, or Redundant Array of Independent Disks, is a data storage virtualization technology that combines multiple physical disk drives into one or more logical units. This is done for the purposes of data redundancy, performance improvement, or both. RAID configurations can vary widely, each offering different balances of these benefits.

Common RAID levels include RAID 0, RAID 1, RAID 5, and RAID 6. RAID 0, also known as striping, offers performance gains by splitting data across multiple drives, but provides no redundancy. If one drive fails, all data is lost. RAID 1, or mirroring, writes identical data to two or more drives, providing excellent redundancy but no performance increase. If one drive fails, the system can continue operating from the mirrored copy.

RAID 5 uses block-level striping with distributed parity. This means data is striped across multiple drives, and parity information, which can be used to reconstruct lost data, is also distributed across all drives. This offers a good balance of performance and redundancy, with the ability to tolerate a single drive failure. RAID 6 is similar to RAID 5 but uses two distributed parity blocks, allowing it to withstand the failure of up to two drives.

Other RAID levels, such as RAID 10 (a combination of RAID 1 and RAID 0), exist to offer further specialized benefits. The choice of RAID level depends on the specific needs for data protection, performance, and cost. RAID systems are widely used in servers, network-attached storage (NAS) devices, and other applications where data reliability and speed are critical.