Does deleting a partition below Ubuntu mess up grub?

[Tom H]

On Sun, Oct 12, 2014 at 10:49 AM, Colin Law <clanlaw at gmail.com> wrote:
>
> So if I want to delete a partition should I first edit
> /boot/grub/grub.cfg, and if so can I assume that all sda numbers above
> the deleted one will be decremented? Or can I run gparted from the
> working system, unmount the partition I want to delete (assuming it is
> not in use), delete it, and run update-grub before re-booting? I
> suspect that will not do anything as the new partition numbers will
> not get allocated until re-boot.
>
> I mis-typed, it is actually sda3 I want to delete. However, when I
> look at the partition numbering it looks a bit strange, so I am not
> sure how to predict what the sda numbers will be after deleting sda3.
> I have
>
> /dev/sda1          Windows
> /dev/sda3          To be deleted
> /dev/sda4          /home
> /dev/sda2  Extended
>     /dev/sda5      /
>     /dev/sda6      Swap
>
> I wonder why grub does not use UUIDs.

You can delete sda3. It won't affect the numbering or grub.

grub does use UUIDs, in the "search ... --set=root <UUID>" and the
"linux ... root=UUID=<UUID> ..." lines in "/boot/grub/grub.cfg".

You can check "/boot/grub/grub.cfg" to make sure that:

- the UUID in the "search ..." lines corresponds to the filesystem of "/boot"

- the UUID in the "linux ..." lines corresponds to the filesystem of "/"