Recover LVM Boot partition within a live CD (installing GRUB)

This allows you to recover the Master Boot record when a RAID 5 array fails.

1. Activate LVM partitions

   sudo mdadm --assemble --scan
   sudo vgchange -a y [name of volume group]

2. Mount all volumes to a single mount-point

   sudo mount /dev/mapper/[volume group]/[root volume] /mnt/
   sudo mount /dev/mapper/[volume group]/[usr volume] /mnt/usr/
   sudo mount /dev/mapper/[volume group]/[home volume] /mnt/home/
   ... etc

3. Mount and bind directories for grub to detect the underlying hardware

   sudo mount --bind /dev /mnt/dev
   sudo mount --bind /dev/pts /mnt/dev/pts
   sudo mount --bind /proc /mnt/proc
   sudo mount --bind /sys /mnt/sys

4. Jump into the new mounted system

   sudo chroot /mnt

5. Install GRUB

   grub-install /dev/sda
   grub-install --recheck /dev/sda
   update-grub

6. Exit the environment and restart

   exit
   sudo umount /mnt/dev/pts
   sudo umount /mnt/*
   sudo shutdown -r now