LVM Root

How to boot from a lvm root disk:

Grab the latest grub from ftp://alpha.gnu.org/gnu/grub/, eg. grub-1.96.tar.gz
Untar the package, change into newly created directory, call ./configure && make && make install
Become root, call /usr/local/sbin/grub-install --modules="pc gpt" /dev/sda or whatever the first bios drive is

Open (or create) the grub config file /boot/grub/grub.cfg with your favorite text editor; a minimal one looks like this:

set timeout=2
set root=(VGSys00-LVRoot00)
insmod linux
menuentry "Linux" {
  linux /boot/vmlinuz root=/dev/ram0 lvmroot=/dev/VGSys00/LVRoot01
  initrd /boot/finitrd
}

You definitely need an initial ramdisk which activates your volume group before the kernel tries to mount the real root filesystem

If any physical volumes of your logical root volume are missing, then you have to call lvm commands with the -P or --partial flag. All logical volumes on errorneous volume groups are in ready-only state, even if you have setup a mirrored logical volume (aka soft RAID-1). Calling blockdev --setrw /dev/VGSys00/LVRoot01 may help in such a situation.

LVM Root

Links