Configure "Raid 0" in Linux

Configuring RAID 0 (striping) on CentOS 9 involves combining multiple disks into a single RAID array to improve performance through data striping across the disks. However, RAID 0 does not provide redundancy, so data loss can occur if any one of the disks fails. Here's a step-by-step guide to set up RAID 0 using mdadm on CentOS 9:

Step-by-Step Guide to Configure RAID 0 on CentOS 9

Step 1: Install Required Packages

Ensure that mdadm (the utility for managing RAID arrays) is installed on your CentOS system. If it's not installed, you can install it using the following command:

sudo dnf install mdadm

Step 2: Identify Disks

Identify the disks that you want to use for RAID 0. For this example, let's assume you have two disks: /dev/sda and /dev/sdb.

Step 3: Partition Disks

If your disks are new or need reconfiguration, you should partition them appropriately. You can use tools like fdisk, parted, or gdisk to create partitions on each disk. For RAID 0, we'll use the entire disk space for each partition.

sudo fdisk /dev/sda
# Create a new partition (e.g., /dev/sda1) covering the entire disk

sudo fdisk /dev/sdb
# Create a new partition (e.g., /dev/sdb1) covering the entire disk

Step 4: Create RAID 0 Array

Now, create the RAID 0 array using mdadm:

sudo mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sda1 /dev/sdb1

• /dev/md0 is the name of the RAID device.

• --level=0 specifies RAID level 0 (striping).

• --raid-devices=2 specifies the number of devices in the RAID array (in this case, two disks).

• /dev/sda1 and /dev/sdb1 are the partitions we created earlier on /dev/sda and /dev/sdb.

Step 5: Verify RAID Configuration

Check the status of the RAID array to ensure it was created successfully:

sudo mdadm --detail /dev/md0

This command provides detailed information about the RAID array md0, including its status and devices.

Step 6: Create a Filesystem

Next, create a filesystem on the RAID array. For example, to create an ext4 filesystem:

sudo mkfs.ext4 /dev/md0

Step 7: Mount the RAID Array

Create a mount point and mount the RAID array:

sudo mkdir /mnt/raid0
sudo mount /dev/md0 /mnt/raid0

Step 8: Configure Mount at Boot

To ensure the RAID array mounts automatically at boot time, add an entry to /etc/fstab:

echo '/dev/md0   /mnt/raid0   ext4   defaults   0 0' | sudo tee -a /etc/fstab

Step 9: Test and Verify

Reboot your system to test if the RAID array mounts automatically and correctly. After rebooting, verify that the RAID array is still operational:

sudo mdadm --detail /dev/md0

Ensure that both disks (/dev/sda1 and /dev/sdb1) are active and in sync (U state).

Additional Notes:

• Always replace /dev/sda1, /dev/sdb1, etc., with the appropriate partitions on your disks.

• Customize RAID level (--level), RAID device name (/dev/md0), filesystem type (ext4), and mount point (/mnt/raid0) as per your requirements.

• RAID 0 provides performance benefits through striping but does not offer redundancy. A failure of any disk in the RAID 0 array will result in data loss.

• Monitor the RAID array regularly (sudo mdadm --detail /dev/md0) to ensure both disks are functioning properly.

By following these steps, you can successfully set up RAID 0 (striping) on CentOS 9 using mdadm, enhancing disk performance by distributing data across multiple disks.