Linux RAID

Linux  RAID

RAID(Redundant Array of Inexpensive Disk or Redundant Array of Independent Disk) is a way of storing the data in different places on multiple hard disks.

Purpose of RAID

It is used to increase the logical capacity of storage devices,to improve read / write performance and ensure redundancy in case of a hard disk failure.

Advantages of RAID

  • To increase the Reliability and performance of the system
  •  Improved redundancy in the case of a failure in some RAID configurations.

Disadvantages of RAID

  • Large number of hard disks,leading to an increased failure rate.
  • Greater difficulty in performing backups and system rescue or restore in the case of a failure.

RAID LEVELS

 RAID-0

The Data will be stored in alternate hard disk. striping, max capacity, max performance, no fault tolerance,

* Need Minimum 2 hard disk or partition

Adv:

Data writing and reading speed is very high.

Dis adv:

Even single hard disk fails ,we cant able to recover the data

 

RAID-1

The Data will be available in both hard disk. mirroring, least capacity, moderate performance, best fault tolerance.

* Need Minimum 2 hard disk or partition.

 Adv :

If single hard disk fails ,we recover the data easily.

Dis adv :

Data writing and reading speed is very low ,when comparing to RAID 0.

RAID-5

The data will be available in all hard disks. Single parity, good capacity, good performance, single drive failure tolerance,

* Need Minimum 3 hard disk or partition.

 Adv :

        *  Even a single hard disk crashes ,we can recover data using two hard disks.

         * Writing and reading speed is very high comparing RAID-0 and RAID-1

Dis Adv :

        * If two hard disk fails ,we cant able to recover the data.

        * Cost is very high.