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Notes From RAID Training..


!!!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