Re: managing a multiboot without stomping the toes of other OSes

[Felix Miata]

On 2011/01/14 14:43 (GMT+0530) Rustom Mody composed:

> I have a system with ubuntu on sda5 and debian on sda6 and a dedicated
> grub partition on sda3 (mbr points to sda3)
> The sda3 grub.cfg only chainloads to sda5 with title ubuntu and
> likewise sda6 with title debian.
> Further bootsector grubs in sda5 and 6 manage the detailed linux options.

> The problem is that whenever some package is updated (eg grub-pc) it
> 'detects' other OSes and makes a grub.cfg with all kinds of junk such
> as the debian kernel with the ubuntu filesystem etc etc.  What is
> worse, it meddles with the sda3/mbr grub

> So what I want is that I should be able to tell the Debian grub:
> 1. You are sitting on sda6 (not sda)
> 2. So please leave sda alone
> 3. Please dont 'detect' other OSes

Put in each /etc/default/grub:

         GRUB_DISABLE_OS_PROBER=true

As extra insurance, I've been removing:

        /etc/grub.d/30_os-probe*

Since I'm a mostly a non-Debian user and I've always remembered to specify / 
or /boot as a Grub target during OS installation, I've never yet needed to 
move a Grub2 location or figure out how it's done. NAICT, one would do this 
by specifying the /boot or / target as a device name running grub-install. 
See: https://help.ubuntu.com/community/Grub2

Another option to consider is installing grub-legacy to sda3 and/or mbr and 
using its chainloader to reach sda5 & sda6. Typically I pre-partition and 
boot a Knoppix disk to mkfs and install Grub1 on a virgin HD before 
installing any operating systems. On multiboot systems I keep a separate 
realboot /boot partition that I never mount as /boot and from which I either 
load default kernel/initrd sets from specified partitions, or chainload to 
specified partitions.

One can always expect stepped on toes when multibooting and accepting the 
usual installation default to install a bootloader to the MBR. Thus I find 
MBR as default bootloader location as policy to be ludicrous. Any OS that 
insists on MBR as bootloader location I abort and/or eradicate from my 
systems. Grub on MBR is rarely necessary. I've never needed it, while I have 
many machines with up to 25 or more installed operating systems.
--
"How much better to get wisdom than gold, to choose
understanding rather than silver." Proverbs 16:16 NKJV

 Team OS/2 ** Reg. Linux User #211409

Felix Miata  ***  http://fm.no-ip.com/