Prerequisites – RAID , RAID levels
1. RAID 1 :
RAID 1 is also known as the mirror configuration of data as it replicates the data from drive 1 to drive 2. In RAID 1, one of the drives is used to store the data and another one acts as a mirror to the already stored data. This level of RAID provides 100% data redundancy in case of any failure.
It has good fault tolerance i.e. ability to maintain functionality even if one disk fails.
It is expensive because the extra drive is required for mirroring.
2. RAID 5 :
In RAID 5, data is equally divided in all disks and minimum number of physical disks needed is 3. The main advantages of RAID 5 over RAID 1 are no need of large space, supports data accessing at the time of recovery and high security of data. RAID 5 is generally suited for medium level of applications.
RAID 5 was introduced to make the random write performance better.
RAID 5 allows recovery of at most 1 disk failure (because of the way parity works). If more than one disk fails, there is no way to recover the data.
Difference between RAID 1 and RAID 5 :
|S.No.||RAID 1||RAID 5|
|1.||RAID 1 stands for Redundant Array of Independent Disk level 1.||RAID 5 stands for Redundant Array of Independent Disk level 5.|
|2.||In RAID 1, data is not split in the disks.||In RAID 5, data is equally divided in all disks.|
|3.||The write speed of RAID 1 is slower than RAID 5.||The write speed of RAID 5 is better than RAID 1.|
|4.||In RAID 1, minimum number of physical disks needed is 2.||In RAID 5, minimum number of physical disks needed is 3.|
|5.||RAID 1 supports mirroring and redundancy.||RAID 5 does not support mirroring and redundancy.|
|6.||Data accessing rate is low in RAID 1.||Data accessing rate is high in RAID 5.|
|7.||In RAID 1, large space is needed for mirror spacing.||In RAID 5, large space is not needed.|
|8.||In RAID 1, we cannot access data at the time of recovery.||In RAID 5, data can be accessed while recovering data from failure.|
|9.||Security of data is low in RAID 1.||Security of data is very high in RAID 5.|
|10.||RAID 1 is best suited for high-end level of applications.||RAID 5 is generally suited for medium level of applications.|