Before we proceed towards the tutorial for Reinstallation of GRUB boot loader on Linux Dedicated Servers, I would suggest you to have a look at the short description about GRUB boot loader which is given below.

Most of us who belong to the web hosting industry are well aware of the fact that the products and applications released under the GNU project are free. GRUB is also a boot loader package which is available for free i.e. it is released under the GNU project. Now, I would like to explain what does GRUB do.

GRUB is actually one of the multiboot specification which will allow you to install and run 2 different operating systems of the same machine. As you will have 2 different operating systems installed on the machine, you will need an option to select the operating system you wish to run when the machine starts, otherwise this feature won't be useful. This option is available if you have GRUB installed on the Linux Dedicated Server Hosting. Alongwith this feature, you can also select different images of the kernel and pass boot time parameters on a single operating system's partitions to such kernels.

Most of the hosting providers who offer Linux Dedicated Servers will assist you to install GRUB boot loader on the Linux Dedicated Servers, however, it might be possible that you will have to reinstall it on your Linux Dedicated Server Hosting. For this purpose, below are some steps which can be followed in order to reinstall GRUB boot loader on Linux Dedicated Servers.

Important : The steps given below are for RedHat and CentOS operating systems only and the steps should be followed in rescue mode. Also, the steps given below are to reinstall a grub which is deleted by mistake or which is corrupted due to some reason.

1. Firstly, it is important to boot the system and hence you should do this before you proceed.

2. As the installation is to be done in the rescue mode, you should enter the rescue mode first and you can do this by entering the Linux rescue command as given below.

Note : Make sure that you enter the Linux rescue command at the installation prompt.
Quote:
linux rescue

3. In order to mount the root partition, enter the command given below :
Quote:
chroot /mnt/sysimage

4. /dev/hda is the boot partition where you need to reinstall the GRUB boot loader and you can enter the command below to do so.
Quote:
/sbin/grub-install /dev/hda

5. Check the file /boot/grub/grub.conf again.

Reason for the confirmation : It might be possible that some additional entries may be needed for GRUB.

6. There is only step to follow i.e. Reboot the system and you are done.

7. Congratulations as you have already Reinstalled GRUB boot loader on your Linux Dedicated Server Hosting.