RAID - Use Of Multiple Hard Drives For High Storage And Reliability

Redundant Arrays of Inexpensive Disks (RAID) was introduced to increase the level of storage, redundancy and augmented performance in enterprises and server markets, but now have become much common with an end user over the past 5 years.

In simple terms, RAID can be defined as a combination of number of low cost hard drives linked together to form a single large capacity storage device with improved performance, high storage capacity and reliability of data storage. Use of RAID storage technology came into significance in late 1980s and has marked its presence as the in-demand data storage medium for corporates, professionals, manufacturing units and individual users for their need of high capacity data storage device.

Generally three forms of RAID are used for desktop computer systems – RAID 0, RAID 1 and RAID 5.

RAID 0 is the lowest level of RAID. This level fails to provide any level of redundancy for the data stored in array. If any of the drive fails, all the data is damaged.

RAID 1 provides simple form of redundancy for data with the help of mirroring process. This RAID level has two individual drives with same capacity. One is the active drive and the second is secondary drive termed as mirror. When data is written to the active drive, it automatically gets copied to the mirror drive.

RAID 5 is the most powerful and effective level of RAID used on desktop computer system. It requires hardware controller card to manage the array but in some desktop operating system it can be done through software. A minimum of three drives are required to build RAID 5 array with similar drives for best performance.

Other levels of RAID levels are RAID 0+1, RAID 10 or 1+0, software and hardware RAIDs which are used for the storage of data.

Advantages of RAID:

Redundancy:

Redundancy becomes the most important feature while developing the RAID server environment. Redundancy is required in means of performing backup of data in situations of drive failure in the array.

Capacity:

By combining multiple small drives into a large array, capacity to store large amount of data increases. The data storage capability of the operating system increases as the RAID server is installed thus providing you the freedom to store any amount of data which gets restricted while using the limited size drives.

Enhanced Performance:

Improved performance can be found in specific versions of RAID and this performance depends upon the number of drives used in the array and the controller. Different RAIDs when implemented provide superior performance in their own way and up to different levels, but all improve in some way or the other.

Lower Cost:

When RAIDs were introduced, the cost of implementing them became a key issue. The invention of RAID was to provide greater storage capacity as compared to use individual high storage capacity device. Difference in the cost of high and low capacity drives can be analyzed with a good example where three drives of small size cost less than an individual high capacity drive which provides more capacity.

Data Security:

The data which is stored on array is completely secured as RAID provides complete security and competence to protect the data. This security is followed even if the complete hard disk fails without any data loss or performing the restoration process of the backed up data. All RAID levels provide same degree of data security.

Improved Accessibility:

Accessibility refers to availability of data. RAID provides its users to recover data from hardware faults without any problems.