Before in the 1980’s and in 1990’s early, information servers of computer were coming across a remarkable enhance in numbers of data they required to store, save and serve. The technologies of storage were receiving very costly to put a large amount of hard drives with high power or capacity in the servers. A solution was required and therefore RAID was created.
Basically the RAID is short form of Redundant Array of Inexpensive Disks. It was a remarkable and outstanding development that was made as a large number of inexpensive hard drives which may possibly connected simultaneously to structure a device of storage having large capacity that presented advanced and improved performance, capacity of storage and consistency over the solutions of older storage. It has been used universally and widely and organized process for enterprise storage and markets related to server, but more than last 5 years has developed too much familiar in systems of end user.
Types of RAID:
There are two possibilities of RAID which are:
The systems which are based on hardware deals with the subsystem of RAID separately from the host and they are represented to the single host only a disk for each RAID array.
SCSI controller is RAID device hardware’s example and supports the RAID array as a specific SCSI drive. An outer system of RAID shifts all RAIDS managing “intelligence” into a manager or controller situated in the outer subsystem of disk. The entire subsystem is associated or linked to the host through a common SCSI controller and as a single disk it has appeared to the host. RAID controllers appear in the mode of cards perform such as a SCSI controller to the system, but manage all of the genuine communications of drive themselves. In these situations, RAID controllers are plugged the drives such as you will do a SCSI controller, but you include them to configured RAID controller, and its difference can never known by the operating system.
Several RAID levels are implemented by software RAID inside the block device or kernel disk secret code. It provides also low cost solution possibly: There is no need of hot-swap framework or costly card of disk controller, while software RAID performs with inexpensive Integrated Drive Electronics disks (IDE) and SCSI disks. Software RAID functioning can extremely well with central processing units (CPU) of high-speed nowadays. The process and function of array based on software is completely dependent or reliant on the load and function of server CPU.
Advantages of RAID
There are three basic reasons or benefits that RAID was used:
- Increased or improved Performance
- Inexpensive/ Lower Costs
1. Redundancy is the basic and important element in the progress of RAID for environments of server. This permitted for the data of backup form in the storage range in the failure occurrence. If any drive is failed in array, it may be move the slow-access from fast-access or swapped out for an original or another drive devoid of switching the system of or deactivated the system, or even redundant drive can be executed. The version which is used by RAID is that on which the redundancy method also depends.
2. The increased or improved performance/ function is only located when particular RAID versions are utilized. On the amount of drives, performance will depend which is also utilized by the controller and the array.
3. Lower costs are also major benefit of RAID. Cost was a major issue when RAID values and demands were being progressed due to its development. The purpose of the array of a RAID is to facilitate the similar or high capacity of storage for an operating system as compared to another usage of hard drives with greater capacity by a single person. A better example can be observed the difference in prices within lower or higher capacity hard drives.