RAID (Redundant Array of Inexpensive Disks)

RAID (Redundant Array of Inexpensive Disks)

Create 3 partitions for implementing RAID using fdisk command.

e.g. #fdisk /dev/hda

Press n to create the 3 new partitions each of 100Mb in size.

Press p to see the partition table.

Press t to change the partition id of all the three partitions created by you to fd (linux raid auto).

Press wq to save and exit from fdisk utility in linux.

#partprobe

Use fdisk -l to list the partition table.

Creating RAID

# mdadm --create /dev/md0 --level=5 --raid-devices=3 /dev/hda6 /dev/hda7 /dev/hda8

Press y to create the arrays.

To see the details of raid use the following command: -

# cat /proc/mdstat

# mdadm --detail /dev/md0

Creating the file system for your RAID devices

#mkfs.ext3 /dev/md0

Mounting the RAID partition

#mkdir data

# mount /dev/md0 data

#df -h /root/data (Command is used to see the space allocation).

Crashing the raid devices

# mdadm --manage /dev/md0 --fail /dev/hda8

Removing raid devices

# mdadm --manage /dev/md0 --remove /dev/hda8


Adding raid devices

# mdadm --manage /dev/md0 --add /dev/hda8

View failed and working raid devices

# cat /proc/mdstat

# mdadm --detail /dev/md0

# tail /var/log/messages

To remove the RAID follow these steps: -

1) unmount the mounted directory where raid is mounted.
e.g. umount data
2) Stop the device
e.g. mdadm --stop /dev/md0
3) View the details of your raid level using following command: -
#cat /proc/mdstat
#mdadm --detail /dev/md0