Bootgrub¶

After a VM reboot, if it doesn’t boot entirely and block on initramfs shell like this :

early console in decompress_kernel
Decompressing Linux... Parsing ELF... done.
Booting the kernel.
Loading, please wait...
Gave up waiting for root device. Common problems:
  - Boot args (cat /proc/cmdline)
     - Check rootdelay= (did the system wait long enough?)
     - Check root= (did the system wait for the right device?)
   - Missing modules (cat /proc/modules; ls /dev)
ALERT! /dev/disk/by-uuid/5e41bf3d-c79c-4b4f-8c82-70f997399634 does not exist.
Dropping to a shell!
modprobe: module ehci-orion not found in modules.dep
(initramfs) _

Finish the boot with :

(initramfs) lvm
lvm> vgscan
[blabla]
lvm> vgchange -ay
[message confirmant la prise en compte de votre lvm]
lvm> exit
(initramfs) exit
[suite de la sequence de boot]

Other possible fix :

http://www.claudiokuenzler.com/blog/442/grub2-boot-issue-error-alert-dev-disk-by-uuid-does-not-exist#.VSZAV1lIjRZ

tl;dr> After getting a boot, update-grub command should resolve the problem (to confirm)

Or before rebooting, trying :

lvm
lvm> vgscan
lvm> vgchange -ay
lvm> exit

rm -f /boot/grub/device.map

grub-mkdevicemap

update-grub