Creating and Managing a RAID Array in SUSE Linux Enterprise

Get the names of the drives with no partitions

lsblk

Your output should match the below (the drives you'll be using later are nvme0n1, nvme1n1, and nvme2n1):

NAME        MAJ:MIN RM SIZE RO TYPE MOUNTPOINT
nvme0n1     259:0    0   2G  0 disk
nvme1n1     259:1    0   2G  0 disk
nvme2n1     259:2    0   2G  0 disk
nvme3n1     259:3    0  10G  0 disk
├─nvme3n1p1 259:4    0   2M  0 part
├─nvme3n1p2 259:5    0  20M  0 part /boot/efi
└─nvme3n1p3 259:6    0  10G  0 part /

Create partitions on the drives, performing the following for each drive:

sudo fdisk /dev/nvme0n1
Then press n for new
Then press p for primary
Then press 1 for the partition number
Then enter for starting/first sector
Then enter for ending/last sector
Then w to write the changes

Prompt the kernel to reread the partition table for the drive:

sudo partprobe /dev/nvme0n1

Repeat the steps for all three drives.

Verify that mdadm is installed:

rpm -q mdadm

Create the RAID 1 using two of the drives:

sudo mdadm --create /dev/md0 --level=1 --raid-devices=2 /dev/nvme0n1p1 /dev/nvme1n1p1

Watch it being created:

sudo watch cat /proc/mdstat

Hit Ctrl+C to quit.

Now the array is complete, check the status:

sudo mdadm --detail /dev/md0

Create the filesystem:

sudo mkfs.xfs /dev/md0

Create a directory and then mount the RAID volume into the directory:

sudo mkdir /mnt/raid1
sudo mount /dev/md0 /mnt/raid1

Verify the RAID size is correct and the mount displays:

lsblk

Note that your array is shown in the output, including the mount point:

nvme0n1     259:0    0   2G  0 disk
└─nvme0n1p1 259:9    0   2G  0 part
  └─md0       9:0    0   2G  0 raid1 /mnt/raid1
nvme1n1     259:1    0   2G  0 disk
└─nvme1n1p1 259:10   0   2G  0 part
  └─md0       9:0    0   2G  0 raid1 /mnt/raid1
nvme2n1     259:2    0   2G  0 disk
└─nvme2n1p1 259:7    0   2G  0 part
nvme3n1     259:3    0  10G  0 disk
├─nvme3n1p1 259:4    0   2M  0 part
├─nvme3n1p2 259:5    0  20M  0 part  /boot/efi
└─nvme3n1p3 259:6    0  10G  0 part  /

Compress the messages file, and place it in the newly created raid1 directory:

sudo tar -czvf /mnt/raid1/messages.tar.gz /var/log/messages

Verify the data is in place and the file is not empty:

ls -l /mnt/raid1

Set one drive to faulty:

sudo mdadm --manage --set-faulty /dev/md0 /dev/nvme1n1p1

Confirm that the drive is in a faulty state:

sudo mdadm --detail /dev/md0

Remove the faulty drive from the array:

sudo mdadm --manage --remove /dev/md0 /dev/nvme1n1p1

Confirm that the drive has been removed:

sudo mdadm --detail /dev/md0

Add the drive to the array:

sudo mdadm --manage --add /dev/md0 /dev/nvme2n1p1

Watch the rebuild:

sudo watch cat /proc/mdstat

Hit Ctrl+C to quit.

Once the rebuild is complete, confirm that the array shows all drives synced:

sudo mdadm --detail /dev/md0

Confirm that the data is still present:

ls -l /mnt/raid1

Re-add the failed drive back to the array as a spare:

lsblk

Note the nvme1n1p1 partition is not currently linked to the array — that's the one to add back in:

NAME        MAJ:MIN RM SIZE RO TYPE  MOUNTPOINT
nvme0n1     259:0    0   2G  0 disk
└─nvme0n1p1 259:9    0   2G  0 part
  └─md0       9:0    0   2G  0 raid1 /mnt/raid1
nvme1n1     259:1    0   2G  0 disk
└─nvme1n1p1 259:10   0   2G  0 part
nvme2n1     259:2    0   2G  0 disk
└─nvme2n1p1 259:7    0   2G  0 part
  └─md0       9:0    0   2G  0 raid1 /mnt/raid1
nvme3n1     259:3    0  10G  0 disk
├─nvme3n1p1 259:4    0   2M  0 part
├─nvme3n1p2 259:5    0  20M  0 part  /boot/efi
└─nvme3n1p3 259:6    0  10G  0 part  /

Add the drive to the array as a spare:

sudo mdadm --manage /dev/md0 --add /dev/nvme1n1p1

The resulting output should be:

mdadm: added /dev/nvme1n1p1

Verify that the drive is added to the array as a spare:

sudo mdadm --detail /dev/md0