Ch 12 RAID

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Redundant Array of Independent / Inexpensive Disk

In raid level we can connect more than 1 means 2 HDD or more in 1 PC.

RAID0 called as Stripped , possible with 2 or 3 HDD.

Strip is for users who wants more space Like 3 HDD of 80 GB become

1 Logical Volume of 240 G.B.

RAID1 Mirror

HDD

80GB

HDD 80GB

# it’s copy all data from 1 Hdd to 2 Hdd As data comes in first HDD

It will give allot only 80 G.B space from 2 X 80 G.B Hdd.

Minimum 2 Hdd Required.

RAID5

Minimum 3 HDD required.

It’s fault tolerant Array.

In short Stripe with parity code.

IF Hdd Array In RAID5 it’s write data as following.

how it writes “ REDUNDANT “ in RAID 5.

R

D

(P)

A

T

E

(P)

N

(P)

U

D

(P)

HDD1 HDD2 HDD3

Here (p) is party code written by RAID5 Controller.

If any single drive goes down how ever we will able to recover redundant word from (p) code and remaining HDD.