RAID OVER LOOP DEVICES (RAID 5)

In this tutorial we will learn how one can configure RAID over loop devices. For demonstration i have created RAID-5 here over loop devices.

First we Need to Create three files.

Here I have created three files of equal size. each 1GB

• create 3 files = a.txt ,b.txt  and c.txt

• dd if=/dev/zero of=a.txt bs=1M count=1000

• dd if=/dev/zero of=b.txt bs=1M count=1000

• dd if=/dev/zero of=c.txt bs=1M count=1000 (2nd formula copy a.txt #cp a.txt b.txt c.txt) copy same size file

• ls -lh show the fileattach file with the loop devices because loop devices has no size.

• losetup /dev/loop1 a.txt

• losetup /dev/loop2 b.txt

• losetup /dev/loop3 c.txtcreate raid 5 using loop devices 

• mdadm –create /dev/md0 –level=5 –raid-devices=3 /dev/loop1 /dev/loop2 /dev/loop3

• mdadm –detail /dev/md0 ( to check  raid devices detail)

• cat /proc /mdstat (check sysconize)

• format= mkfs.ext3 /dev/md0

• mkdir /B

• mount /dev/md0 /B

• umount /B

• mdadm –stop /dev/md0

• mdadm –remove /dev/md0

• losetup -d /dev/loop1

• losetup -d /dev/loop2

• losetup -d /dev/loop3

• delete file = # rm -rf *.txt