Grub2 disaster recovery¶

Requirements¶

To install such a system you will need the following:

• Download Fedora 18 Live DVD or a newer version of Fedora supporting Grub2 and burn it on an empty CDROM (the .iso can be found here: http://fedoraproject.org/get-fedora)
• a bootable CDROM-drive

alternatively you might use a bootable USB-drive created with the Fedora LiveUSB Creator

Preliminary Note¶

It is assumed that

• the first harddrive (sda) is the system-drive.
• the root filesystem to be recovered is in a logical group/volume called /dev/vp_p2600f18/lv_f18_root
• the boot filesystem to be recovered is in a partition called /dev/sda8
  These settings might differ for you, so you have to replace them where appropriate.

Some very important information is take from https://fermilinux.fnal.gov/documentation/tips/mount-bind-chroot

Many times when you are fixing a machine, you need to chroot into it. Many of those times the programs you run (such as grub-install) will need the /proc, /dev, and /sys directories to be alive and well. This is when you need to use bind.

Start Fedora 18 Live DVD¶

list all partitions

fdisk -l

list all logical volumes

lvdisplay

create a base directory for the system to be rescued

mkdir /mnt/f18

mount the 'root'-filesystem

mount /dev/vp_p2600f18/lv_f18_root /mnt/f18

mount the 'boot'-filesystem

mount /dev/sda8 /mnt/f18/boot

bind the /proc, /dev, /sys into the to be rescued 'root'-filesystem

mount -o bind /proc /mnt/f18/proc/
mount -o bind /dev /mnt/f18/dev/
mount -o bind /sys /mnt/f18/sys

chroot and install Grub2

chroot /mnt/f18
grub2-install /dev/sda
exit

restart the machine and test the result