TipsOnRaid10

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Find how many disks are available in system:

# fdisk -l

Examine the detailed info:

# lsblk -o NAME,SIZE,FSTYPE,TYPE,MOUNTPOINT
NAME     SIZE FSTYPE  TYPE MOUNTPOINT
loop0  876.9M iso9660 loop /media/cdrom
sda    557.9G         disk 
├─sda1   512M vfat    part /boot/efi
└─sda2 557.4G ext4    part /
sdb      3.7T         disk 
sdc      3.7T         disk 
sdd      3.7T         disk 
sde      3.7T         disk 
sdf      3.7T         disk 
sdg      3.7T         disk 
sdh      3.7T         disk 
sdi      3.7T         disk 
sdj      3.7T         disk 
sdk      3.7T         disk 
sdl      3.7T         disk 
sdm      3.7T         disk

Create the raid10 using following command:

#  mdadm --create --verbose /dev/md0 --level=10 --raid-devices=12 /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi /dev/sdj /dev/sdk /dev/sdl /dev/sdm

View the status, now you could use it:

#  cat /proc/mdstat

Make filesystem for using:

# mkfs.ext4 -F /dev/md0

Create mount point and mount the md0:

# mkdir -p /media/md0
# mount /dev/md0 /media/md0
# df -h

Add md items to mdadm configuration file, so next time bootup kernel will recognize it, also add fstab items:

#  mdadm --detail --scan | sudo tee -a /etc/mdadm/mdadm.conf
#  cat /etc/mdadm/mdadm.conf 
#  update-initramfs -u
#  echo '/dev/md0 /mnt/md0 ext4 defaults,nofail,discard 0 0' | sudo tee -a /etc/fstab
#  cat /etc/fstab 

Now view the lsblk output will show like following:

lsblk -o NAME,SIZE,FSTYPE,TYPE,MOUNTPOINT
NAME     SIZE FSTYPE            TYPE   MOUNTPOINT
loop0  876.9M iso9660           loop   /media/cdrom
sda    557.9G                   disk   
├─sda1   512M vfat              part   /boot/efi
└─sda2 557.4G ext4              part   /
sdb      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdc      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdd      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sde      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdf      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdg      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdh      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdi      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdj      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdk      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdl      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0
sdm      3.7T linux_raid_member disk   
└─md0   21.9T ext4              raid10 /media/md0

remove md

via:

sudo mdadm --stop /dev/md0
sudo mdadm --detail /dev/md0
sudo mdadm --zero-superblock /dev/sdx
sudo mv /etc/mdadm/mdadm.conf /etc/mdadm/mdadm.conf.bak