RAID(Redundant Array of Inexpensive/Independent Disk) :
RAID technology is used for creating copy of the original data, so that if the system fail data can be recover. The RAID was first coined by a research group at University of California, Berkeley, to describe a collection of disk drives(disk array).
Type of RAID :
1) Hardware :
When a disk controller manage disk array, it is known as Hardware RAID.
2) Software RAID :
Here OS manage disk array, it is known as Software RAID.
RAID Management Command :
- raid start (Start RAID)
- raid stop (Stop RAID)
- raid reconfig (To add or remove copy)
RAID Level :
For short description click here…
RAID 0(No Redundancy) :
As the name suggest “No Redundancy”. There will be no copy disk will be maintain in RAID 0.
RAID 1(Mirroring) :
- Exact copy the original disk is maintain.
- That means n original disk is require, n copy disk require.
RAID 2(Error Correcting Code) :
- The RAID 2 focus on the reducing the copy disk environment with respect to RAID 1.
- It’s original disk store data where copy disk stores ECC.
RAID 3(Block Level Parity) :
- RAID 3 further reduce the copy disk requirement with respect to RAID 2 and calculate parity of data .
- The parity is calculated block wise.
RAID 4(Bit Level Parity) :
It is same as RAID 3 but the parity is calculated bit wise.
RAID 5(Distributed Bit Level Parity) :
- It is same as RAID 4.
- It does not maintain separated copy disk and parity bit are distributed such way that every disk will contain only one parity disk.