| Redundant Arrays of Inexpensive Disks | | | | Enhanced Performance |
| (RAID) was introduced to increase the | | | | Improved performance can be found in |
| level of storage, redundancy and | | | | specific versions of RAID and this |
| augmented performance in enterprises and | | | | performance depends upon the number of |
| server markets, but now have become much | | | | drives used in the array and the |
| common with an end user over the past 5 | | | | controller. Different RAIDs when |
| years. | | | | implemented provide superior performance |
| In simple terms, RAID can be defined as | | | | in their own way and up to different |
| a combination of number of low cost hard | | | | levels, but all improve in some way or |
| drives linked together to form a single | | | | the other. |
| large capacity storage device with | | | | Lower Cost |
| improved performance, high storage | | | | When RAIDs were introduced, the cost of |
| capacity and reliability of data | | | | implementing them became a key issue. |
| storage. Use of RAID storage technology | | | | The invention of RAID was to provide |
| came into significance in late 1980s and | | | | greater storage capacity as compared to |
| has marked its presence as the in-demand | | | | use individual high storage capacity |
| data storage medium for corporates, | | | | device. Difference in the cost of high |
| professionals, manufacturing units and | | | | and low capacity drives can be analyzed |
| individual users for their need of high | | | | with a good example where three drives |
| capacity data storage device. | | | | of small size cost less than an |
| Generally three forms of RAID are used | | | | individual high capacity drive which |
| for desktop computer systems - RAID 0, | | | | provides more capacity. |
| RAID 1 and RAID 5. | | | | Data Security |
| RAID 0 is the lowest level of RAID. This | | | | The data which is stored on array is |
| level fails to provide any level of | | | | completely secured as RAID provides |
| redundancy for the data stored in array. | | | | complete security and competence to |
| If any of the drive fails, all the data | | | | protect the data. This security is |
| is damaged. | | | | followed even if the complete hard disk |
| RAID 1 provides simple form of | | | | fails without any data loss or |
| redundancy for data with the help of | | | | performing the restoration process of |
| mirroring process. This RAID level has | | | | the backed up data. All RAID levels |
| two individual drives with same | | | | provide same degree of data security. |
| capacity. One is the active drive and | | | | Improved Accessibility |
| the second is secondary drive termed as | | | | Accessibility refers to availability of |
| mirror. When data is written to the | | | | data. RAID provides its users to recover |
| active drive, it automatically gets | | | | data from hardware faults without any |
| copied to the mirror drive. | | | | problems. |
| RAID 5 is the most powerful and | | | | Disadvantages of RAID: |
| effective level of RAID used on desktop | | | | RAIDs do give an assured security to the |
| computer system. It requires hardware | | | | computer systems but this security |
| controller card to manage the array but | | | | cannot be relied upon for long time. If |
| in some desktop operating system it can | | | | your PC gets attacked by virus, or files |
| be done through software. | | | | and folders are deleted or your PC hits |
| A minimum of three drives are required | | | | the floor or is affected by the fire - |
| to build RAID 5 array with similar | | | | water damage leads to such situations |
| drives for best performance. | | | | where you don't have any other option |
| Other levels of RAID levels are RAID | | | | other than opting for RAID data recovery |
| 0+1, RAID 10 or 1+0, software and | | | | services. There have been many cases |
| hardware RAIDs which are used for the | | | | when more than one drive has failed |
| storage of data. | | | | causing an expensive RAID data recovery. |
| Advantages of RAID: | | | | Like such cases, anything is possible |
| Redundancy | | | | and constant backups should be |
| Redundancy becomes the most important | | | | maintained to avoid data loss situations |
| feature while developing the RAID server | | | | even if you are using any reliable |
| environment. Redundancy is required in | | | | storage medium. |
| means of performing backup of data in | | | | Conclusion: |
| situations of drive failure in the | | | | It is agreed that RAID provides PC users |
| array. | | | | with a number of benefits depending upon |
| Capacity | | | | the version implemented. High storage |
| By combining multiple small drives into | | | | capacity, security, accessibility, |
| a large array, capacity to store large | | | | performance are the key features which |
| amount of data increases. The data | | | | attract users to opt for RAID. The |
| storage capability of the operating | | | | advantage of one RAID level over the |
| system increases as the RAID server is | | | | other cannot be measured as for some |
| installed thus providing you the freedom | | | | applications RAID 5 is better than RAID |
| to store any amount of data which gets | | | | 0 and for some RAID 0 would be superior |
| restricted while using the limited size | | | | to RAID 5. |
| drives. | | | | |