The Raid levels architecture and levels

The Raid levels architecture and levels

RAID stands for Redundant Array of Inexpensive Disks. It is a technology utilized to boost the performance and consistency of data storage. The RAID system is composed of two or more disks that are working in parallel. The disks used in a RAID system can be a hard drive but there is a trend that also uses the technology for SSDs or Solid State Drives.

RAID level 0 – Striping

In this level, data are divided into blocks and get written across every drive in the array. By utilizing multiple disks simultaneously, at least 2, this gives greater Input/Output performance. The advantages for this level include: offers great performance both for the read and write operations, no disk overhead because all storage capacity is used, and the implementation of the technology is easy.

The disadvantage is that level 0 is not fault-tolerant. If one of the disks fails, all data in the array are lost. This level is perfect for non-critical data storage like for example in a Photoshop image retouching shop where data have to be written and read at a high speed.

RAID level 1 – Mirroring

In this level, data are saved two times by writing them both to the data disk and to the mirror disk. The data disk can be a group of data disks and the mirror disk can also be a group of mirror disks. If there is one disk that fails, the controller uses the mirror drive or the data drive for data recovery and continuous operation.

Most of the time RAID level 1 is combined with RAID level 0 to enhance the performance. The advantages for this level include: offers outstanding read speed and the write speed can be compared to that of a single disk, when a disk fails data don’t have to be rebuild because they just need to be copied to the replacement disk, very simple technology.

The main disadvantage for level 1 is that only half of the total disk capacity is the efficient storage capacity for the reason that all data have to be written twice.