RAID1 is also known as Disk Mirroring , It is the technique of writing the same data to more than one disk drive.
Requirement : minimum 2 HDD
Step : 1
Install Required Package
CentOS/Rhel
yum install mdadm
Ubuntu
apt-get install mdadm
Step 2:
Examine Disk Drive
fdisk -l
mdadm /dev/sd[b-c]
Step 3:
Drive Partition
fdisk /dev/sdb
Follow the below instructions
Press ‘n‘ for creating new partition.
Then choose ‘P‘ for Primary partition.
Next select the partition number as 1.
Give the default full size by just pressing two times Enter key.
Next press ‘p‘ to print the defined partition.
Press ‘L‘ to list all available types.
Type ‘t‘ to choose the partitions.
Choose ‘fd‘ for Linux raid auto and press Enter to apply.
Then again use ‘p‘ to print the changes what we have made.
Use ‘w‘ to write the changes.
After ‘/dev/sdb‘ partition has been created Successfully , Follow the same instructions to create new partition on /dev/sdc drive.
fdisk /dev/sdc
Step 4:
Verify the changes on both sdb & sdc drive
mdadm /dev/sd[b-c]
mdadm /dev/sd[b-c]1
Step 5:
Create Raid1
mdadm --create /dev/md0 --level=mirror --raid-devices=2 /dev/sd[b-c]1
Check Process and %
cat /proc/mdstat
Step 6:
Check the raid devices type
mdadm -E /dev/sd[b-c]1
Raid Level : raid1
Raid Devices : 2
Check Device Array
mdadm --detail /dev/md0
Step 7:
Creating File System on RAID Device
mkfs.ext4 /dev/md0
Step 9:
Save Raid Configuration :
Ubuntu:
mdadm --detail --scan >> /etc/mdadm/mdadm.conf
CentOS
mdadm --detail --scan >> /etc/mdadm.conf
Step 9:
Mount Raid Partition : Temp
mkdir /raid1
mount /dev/md0 /raid1
df -h #verify
Mount Raid Partition : Permanent
vi /etc/fstab
/dev/md0 /raid1 ext4 defaults 0 0
mount -a
Raid devices don't really exist on their own; they have to be assembled each time you want to use them
Assemble Raid :
mdadm --assemble /dev/md0 /dev/sda1 /dev/sdb1
Auto Mount Raid1 using systemd service in CentOS 7 / Ubuntu 16... Click Here
Stopping a running RAID device
mdadm --stop /dev/md0
Starting RAID device
mdadm --run /dev/md0
