RAID(Redundant Array of Independent Disk)

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.RAID

2) Software RAID :

Here OS manage disk array, it is known as Software RAID.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

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

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

RAID 4(Bit Level Parity) :

It is same as RAID 3 but the parity is calculated bit wise.RAID

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.