[Mageia-dev] Grub2 vs. Grub Legacy in M3

[Barry Jackson]

On 27/01/13 15:24, Maurice Batey wrote:
> On Sun, 27 Jan 2013 12:31:37 +0000, Barry Jackson wrote:
>
>> my "master" grub2 grub.cfg which is in a small grub
>> partition at the start of sda.
>
>    How does one acquire a 'small grub partition'?
> (Just get GRUB2 package to install into an empty partition?)
>
Yes - in a nutshell
Create a partition preferably near the start of the drive and label it 
"maingrub" then:

mkdir -p /maingrub && \
mount -L maingrub /maingrub && \
grub2-install --root-directory=/maingrub /dev/sda

Now the MBR point to maingrub, but there is no menu yet.
You can manually create a simple grub.cfg - there are examples in the 
grub2 documentation - there's a link in the README
It won't be pretty, but can be made to look nice with a good colour choice.
You could let grub2 create a grub.cfg to get started, but it will be 
over complicated and point directly to the current kernels which is no 
use once kernels get updated. You really need entries that multiboot 
(into grub2) or chainload (into legacy linux).
My current grub.cfg is a bit big as I need to remove some old entries, 
however it may be a good reference for you. The theme references don't 
work - that was just experimental.
http://paste.kde.org/658670/
Copy it quick I think it expires in 24 hours ;)

>> My MBR points to this partition, so all
>> OS's are either chainloaded or multibooted from the manually created
>> entries in this grub.cfg
>
>    Which do you have in the MBR: GRUB2 or Legacy?
Grub2 - have had for the last year or so, but you could also put grub 
legacy in there as well since they can coexist, then simply re-write one 
or the other to MBR to switch ;)

>
>> My limited understanding is that it is similar to chainloading but does
>> not need embedded code in the PBR.
>
>    Ah,now that's interesting!
> (I assume you mean 'does not need GRUB2 installed in the PBR')

Yes
>
>> A useful side effect is that grub legacy may be installed to the PBR and
>> used if required,
>
>     I assume you mean the PBR of the 'small grub partition'.
No - I mean that since grub2 is not using the PBR, legacy can, if you 
wish to have them installed side by side.

>
> Mamy thanks, Barry, especially w.r.t to the 'bootloader' partition!
>
Note that the small grub partition is never mounted and never written to 
by any system (unless you need to modify it of course)
This means that no system can screw it up :) - only you :\