CentOS 7: Reinstall GRUB2 on RAID0 Disks for Dedicated Server

CentOS 7: Reinstall GRUB2 on RAID 0 Disks for a Dedicated Server

In this article, we will discuss the steps required to reinstall GRUB2 on RAID 0 disks for a dedicated CentOS 7 server. This is a common issue faced by server administrators when the server fails to boot and displays the error message "no bootable device found."

Prerequisites

Before we begin, ensure that you have the following:

• Access to the dedicated server via a console or IPMI interface
• Two hard drives connected in hardware RAID 0 configuration
• A CentOS 7 installation media (DVD or ISO image) and a bootable USB or CD

Background

RAID (Redundant Array of Independent Disks) is a technology that combines multiple physical disks into a single logical unit for improved performance and/or data redundancy. RAID 0, also known as striping, is a RAID level that distributes data across multiple disks for improved performance. However, RAID 0 does not provide data redundancy, making it less suitable for critical applications.

GRUB (GRand Unified Bootloader) is a bootloader used in Linux systems to load the operating system kernel and initramfs. GRUB2 is the latest version of GRUB and is used in CentOS 7. In a RAID configuration, GRUB2 must be installed on the boot sector of the RAID array to enable booting from the logical volume.

Reinstalling GRUB2 on RAID 0 Disks

To reinstall GRUB2 on RAID 0 disks, follow the steps below:

1. Boot the server using the CentOS 7 installation media.
2. Select "Troubleshooting" from the boot menu and then "Rescue a CentOS system."
3. Select the language and keyboard layout and then press "Continue."
4. Select the disk where CentOS 7 is installed and then press "Continue."
5. Mount the root file system by running the following command:
   # mount /dev/mapper/centos-root /mnt

6. Mount the boot file system by running the following command:
   # mount /dev/sda1 /mnt/boot

7. Bind the necessary file systems by running the following commands:
   # mount --bind /dev /mnt/dev # mount --bind /proc /mnt/proc # mount --bind /sys /mnt/sys

8. Chroot into the root file system by running the following command:
   # chroot /mnt

9. Reinstall GRUB2 on the RAID array by running the following command:
   # grub2-install /dev/md0

10. Generate the GRUB2 configuration file by running the following command:
    # grub2-mkconfig -o /boot/grub2/grub.cfg

11. Exit the chroot environment and unmount the file systems by running the following commands:
    # exit # umount /mnt/dev # umount /mnt/proc # umount /mnt/sys # umount /mnt

12. Reboot the server and remove the installation media.

In this article, we discussed the steps required to reinstall GRUB2 on RAID 0 disks for a dedicated CentOS 7 server. This is a common issue faced by server administrators when the server fails to boot and displays the error message "no bootable device found." By following the steps outlined in this article, you can reinstall GRUB2 on the RAID array and enable booting from the logical volume.

References

• CentOS 7 Installation Guide

• GRUB2 Manual

• RAID - Wikipedia