Grub confusion

[JARA MELAGRANI, Mariano [wz]]

On 11/12/2013 09:00 a.m., Kevin O'Gorman wrote:
> On Tue, Dec 10, 2013 at 6:56 AM, Jim Byrnes <jf_byrnes at comcast.net> wrote:
>> On 12/09/2013 09:27 PM, Kevin O'Gorman wrote:
>>>
>>> Running xubuntu 13.04, I have 4 large hard drives on the machine, some
>>> of which have been used before as boot drives.
>>>
>>> The BIOS tries to use the first one that it can access that also
>>> contains a bootstrap loader.  I would like to remove the loaders, but
>>> maintain the partition table in all drives but one.
>>>
>>> Is there a handy way to do this?
>>>
>>
>> Does your bios/efi maybe allow you to specify the hard drive to boot from?
>> Mine does and it made swapping out a HD with Ubuntu on it for one with Win 7
>> and still boot from a remaining HD with a different copy of Ubuntu on it.
>>
>> Regards,  Jim
> 
> All drives are MBR formatted.
> 
> I described the situation poorly, reflecting the fact that I'm both
> frustrated and confused.  The 4 drives are the same make and model, so
> the BIOS can't tell me which one is which.  The mobo has 6 internal
> SATA-3 connectors, in a group of 2 and another group of 4, with no
> obvious order.  When I run update-grub, then boot, the grub bootloader
> has a peculiar idea of what kernels there are, that does not entirely
> agree with what's in /boot.  I can boot, but I have to choose the
> kernel carefully.
> 
> This is surely partly a result of the fact that some of those other
> disks still have a Linux image of some kind, almost surely including a
> viable grub boot loader, and some of this shows in the options when
> booting.
> 
> So I'm not sure what drive the boot loader is on.  I'm not sure what
> /boot it's using, so I'm not sure which /boot/grub/menu.cfg it's
> using.
> 
> I want to simplify the situation, at least a bit.  But I do not want
> to lose those other Linux boot options, although I can do without
> their bootloaders and config files -- if only I knew which was which.
> 
> Since I don't know exactly what's happening, I'm leery of destroying
> stuff for fear the system won't boot.  I'm pretty sure that the drive
> that became /dev/sda is the one the BIOS booted from, but I suspect
> that its notion of /boot is different from mine, and it's not being
> updated by update-grub.
> 
> Waiting for clarity and inspiration........
> 
I´m far from being an expert here but, maybe you could edit each /boot/grub/menu.cfg file of every drive and add, for instance, sdx or something like that at the menu´s line, in order that when you boot the system you´d know which drive it´s booted from. Not sure if it´d work, it´s just a thought.

Mariano