Difference between RAID 0,RAID 1 AND RAID 5

Hi Friends,
This was one of the interview question in ORACLE CORPORATION INDIA P.V.T BANGALORE.
Difference between Linux RAID 0, RAID 1 and RAID 5
Dear members,While installing Linux it display information about RAID 0, 1 and 5. I would like to know what is the different between all these RAID options.Which one is the best and why?regards,JO
Ans:

RAID 0
=> Use if you want good read and write performance
=> Strips data across multiple disks
=> No Fault tolerance
=> Good for Workstation computers or application which needs fast disk I/O
=> Minimum requirement: 2 hard disk

RAID 1
=> Use for mirroring (hard disk to hard disk or partition to partition )
=> Fault tolerance => Use this if you want exact copies of data
=> Minimum requirement: 2 hard disks

RAID 5
=> Use for dedicated FILE/App server
=> Combination of RAID 0 and RAID 1
=> Read rate high
=> Write rate medium
=> Use this for database, Internet servers (such as web, mail etc), File server etc
=> Minimum requirement: 3 hard disks



RAID 0:Block striping, yields higher performance than with individual drives. There is no redundancy. ex. disk1 = 80G disk2 = 100G
total space = 160G

RAID 1:Drives are paired and mirrored. All data is 100% duplicated on anequivalent drive. Fully redundant. total space is equal to the size of the smallest disk.ex. disk1 = 80G disk2 = 100G
total space = 80G

RAID 5:Data is striped across several physical drives. Parity protection is usedfor data redundancy. Parity is stored on each disk. (in RAID 3, parity is stored in single disk). supports single disk failure. ex. disk1 = 80G disk2 = 100G disk3 = 120G
total space = 80*2=160G

Thanks,
Rafi.