Wednesday, December 16, 2009

Unfortunate cutoff

If you are writing a piece of text that may be cut off, pay some extra attention to your first sentence…

Sunday, December 6, 2009

Reinstalling GRUB with LVM from the Ubuntu cd

This post is mostly a reminder to myself. Every time I reinstall Windows, it overwrites my boot sector, and I need to reinstall it from the Ubuntu live CD to get my dual-boot system back. However, since my Ubuntu install is inside an LVM partition, this is not very straightforward. Here are the instructions. I kept them general so that they may be of use to someone else as well.

  • Start from the Ubuntu CD and open a terminal.
  • Install LVM:
    sudo apt-get install lvm2
  • Find the name of the volume group:
    sudo vgdisplay
  • Make the volume group available:
    sudo vgchange -ay name-of-vg
  • Mount the root and boot file systems, and bind the dev file system:
    sudo mkdir foo
    sudo mount /dev/name-of-vg/name-of-root-lv foo
    sudo mount /dev/name-of-boot-partition foo/boot
    sudo mount -obind /dev foo/dev
  • Change to the root of your system:
    sudo chroot foo
  • Drop into the GRUB prompt:
    sudo grub
  • Install the GRUB MBR (assuming that (hd0) is your boot drive and (hd0,0) your boot partition):
    root (hd0,0)
    setup (hd0)
  • Reboot and have your boot menu back!