Tuesday, 24 June 2014

RAID: Levels, functions & RAID in OS X Mac


RAID expands to Reduntant Array of Independent Disk, is a data storage technology which coalesces the disk drives into a single logical unit for the purpose of enhancing the performance and data redundancy. Basically RAID is the policy to spread the data across multiple disk in a reliable manner. This technology comprises of certain levels which makes the task of data storage easier.

RAID levels:
The popular levels of RAID are RAID 0, RAID 1,  RAID 5, RAID 6 and RAID 10. RAID 0 is mainly used for striping, that is to read and write the data pararellely across the disk to achieve performance.

The main function of another level RAID 1 is mirroring, which helps to maintain the mirrored sets of the hard drive. In this case, if the hard drive get fails or data is deleted accidently then there is another mirrored drive which consist of the identical data. Although this feature require double storage capacity but it ensures high data protection and performance.

Now comes the RAID 4 which has the splendid characteristic of parity, which is used to detect the fault tolerence. It is used to recover the lost data in case of disk drive failure. RAID 4 consist of 3 hard disk drives in which 1 is for checking parity. One of the most prominent feature of RAID 4 is hot sparing that is it has the power of replacing the failed disk automatically. Inspite of all these features this level is not so commonly used.

The reason is RAID 6 which has 2 parity disk means it has the capacity to replace 2 hard drive failures automatically. Most widely used out of all levels of RAID is RAID 10. However, in this level, order of the required task is maintained. First mirroring is done and then the data is striped across the disk drives. Its is commonly called as the “stripes of mirrors” the fruitful combination of RAID 0 and RAID 1.
RAID in OS X Disk Utility:

Most commonly OS support RAID technology software for managing the volumes such as Mac OS X Disk Utility. Data is distributed across multiple disk either by hardware RAID or software RAID. Software RAID is implemented as a single virtual device which consist of a standard drive controller chip inbuilt into it with the drivers in it as well. Now if we compare this with the hardware RAID then this software RAID involves less number of CPU cycles and power to run.

RAID in Disk Utility is a built in software which support few levels of RAID. Mac OS X disk utility supports RAID 0, RAID 1 and RAID 10. Software RAID is reliable and flexible for the overall functioning of the system as it maintains the storage effectively without any loss of data. The two efficient feature of the Mac OS X Disk Utility is striping and mirroring. Striping stores the files in segments across the disk which is beneficial in when we have to deal with large sets of data whereas mirroring helps to duplicate the content of the data on to the another drive. After clicking on the RAID option in Disk Utility, just choose RAID type and format according to the data requirement and create sets. These sets will helps us to manage the data enthusiastically.

So, the above content describes the introduction and overall view of RAID to utilize the best service in an efficient manner.