Raid Technology Explained!

The word RAID stands for Redundant Array Independent Disks. The idea of RAID technology was to use an array of hard disks for either better performance or better security against disk failure. Raid can use 2 or more disks at once to increase data reading and writing speed, It can use 2 or more disks to store the same data so disk failure will not mean that you lose your data, or RAID can be a mixture of both. A RAID Array of disks will appear to an operating system as a single disk as extra storage space is not provided by RAID.

RAID Levels

There are different RAID levels, each supporting specific situations. RAID levels are not standardized by an industry group. This explains why companies are sometimes creative and come up with their own unique implementations. But we will only discuss the most widely used RAID in the industry.

RAID Level O

RAID 0 diagram

In RAID Level 0, the RAID host adapter sends one part of data to one hard disk and another part of the data to another hard disk. However not only is there no data protection, it is actually less reliable than a single disk, as all the data is lost if a single disk in the array stripe fails. Minimum hard disk needed to implement RAID 0 is 1.

RAID Level 1

RAID 1 Diagram

RAID Level 1 is totally different compare to RAID Level 0. When your PC sends data to be written to the hard disk, the RAID adapter writes an identical image to each of two drives (data mirroring). Two copies of the data are held on two physical disks, and the data is always identical. RAID1 has a performance advantage, as reads can come from either disk, and is simple to implement. However, it is expensive, as twice as many disks are needed to store the data. Minimum hard disk to implement RAID 1 is 2.

RAID Level 5

RAID Level 5 Diagram

RAID Level 5 is the ultimate one. It includes both error correction and performance in the setup, so it is good for corporate or mission critical use. Good general performance, and quite cheap to implement. Used extensively for general data. Minimum hard disk to implement RAID 5 is 3.

RAID Level 10

RAID 10 Diagram

RAID 10 is a combination of RAID1 mirroring and data striping. This means it has very good performance, and high reliability, so it is most ideal for mission critical database applications. All that redundancy means that it is expensive. Minimum hard disk to implement RAID 10 is 4 hard disks.

Advantages of Using RAID drive

Increases the performance and reliability
The RAID drive is a credible example that could be used in a server. The RAID increases the parity check and thus it regularly checks for any possibility of a system crash. Disk stripping is also a hot topic when we discuss about the RAID drives. The performance is much highlighting and increases a lot when the disk stripping is done. How the performance increases a lot by the disk stripping? This is actually done by the interleaving of the bytes or the group of bytes. The interleaving of this sort is done across the multiple drives. By this procedure only one disk is reading or writing the data. The reading and writing of the data are done in a simultaneous process.

Mirroring the complete duplication of the data
Mirroring the duplication of the data on two drives. In other words mirroring is the 100%  redundancy. Only copying to the replacement is necessary.

The concept of parity comes after the concept and application of the mirroring.
The parity involves that the data from the crashed system be matched up with the data that is stored in the other disk. The parity check is the term allotted for the work it carries out. The procedure involved is done as the parity is used to calculate the data in the two drives and store the results in the third drive. In case there are more than two drives the parity check is done on all of them and the results are stored on a completely altogether different drive. The preferable device may be the RAID 3 or the RAID 5. And the failed drive is replaced.

At Shinjiru we provide the option to setup RAID for our dedicated server customers. You can view the fees here. Check it out~

Until next time readers~

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