Multibooting

[Terry Linhardt]

Paul Howarth wrote:

> Satish Balay wrote:
>
>> On Thu, 25 Nov 2004, Paul Howarth wrote:
>>
>>
>>> Satish Balay wrote:
>>>
>>>> An alternative way to install - where no manual intervention is
>>>> required is to have a common '/boot' partition for all OSes - this way
>>>> there is also a common /boot/grub/grub.conf.
>>>>
>>>> So, if you update FC3 kernel - the correct grub.conf is updated.
>>>> And if you update RHL9 kernel - the correct grub.conf is updated.
>>>
>>>
>>> Wouldn't this cause problems:
>>>
>>> 1. because there would have to be two "template" boot entries, one 
>>> for each
>>> OS, and grubby might have trouble figuring out which one to use?
>>
>>
>>
>> Nope - the 'root' parameter will be different for each OS. (and
>> different partitions on the disk. Only /boot - a separate patition is
>> common)
>
>
> Supposing the composite grub.conf looks like this:
>
> # grub.conf generated by anaconda
> #
> # Note that you do not have to rerun grub after making changes to this 
> file
> # NOTICE:  You have a /boot partition.  This means that
> #          all kernel and initrd paths are relative to /boot/, eg.
> #          root (hd0,0)
> #          kernel /vmlinuz-version ro root=/dev/hda5
> #          initrd /initrd-version.img
> #boot=/dev/hda
> default=0
> timeout=10
> splashimage=(hd0,0)/grub/splash.xpm.gz
> title Fedora Core (2.6.9-1.3_FC2)
>         root (hd0,0)
>         kernel /vmlinuz-2.6.9-1.3_FC2 ro root=LABEL=/
>         initrd /initrd-2.6.9-1.3_FC2.img
> title Fedora Core (2.6.8-1.521)
>         root (hd0,0)
>         kernel /vmlinuz-2.6.8-1.521 ro root=LABEL=/
>         initrd /initrd-2.6.8-1.521.img
> title Red Hat Linux (2.4.20-8)
>         root (hd0,0)
>         kernel /vmlinuz-2.4.20-8 ro root=LABEL=/1
>         initrd /initrd-2.4.20-8.img
>
> So, when a new kernel is to be added, how does grubby know whether to 
> add an entry with "root=LABEL=/" or "root=LABEL=/1"?
>
> Paul.
>
As a follow-up to a prior post, here is MY grub.conf file, edited a bit 
for clarity.
I have ONE bootloader, in the MBR. Each verson of Linux has it's own 
/boot partition and it's own root partition.  (In the sample below, root 
is on hda1 (hd0,0) and hda5 (hd0,4). By default, the 2nd installation 
boots (default=1). If I want the first instance to boot, default would 
be set to 0.  Also, I've commented out "hiddenmenu" which I do not like.

Now, when I install a new kernel for the "first" version of Linux 
(Wambach), the grub.conf file automatically updates. But, for any other 
versions I have installed, e.g. Lilly on hd0,4 I need to manually update 
grub.conf on my hda1 partition.

Again, a bootloader was installed for "Wambach", but when I installed 
Lilly I selected "no boot loader."

#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/hda2
#          initrd /initrd-version.img
#boot=/dev/hda
default=1
timeout=15
splashimage=(hd0,0)/grub/splash.xpm.gz
#hiddenmenu
title Fedora Core -Wambach- (2.6.9-1.678_FC3)
        root (hd0,0)
        kernel /vmlinuz-2.6.9-1.678_FC3 ro root=LABEL=/ rhgb quiet
        initrd /initrd-2.6.9-1.678_FC3.img

title Fedora Core - Lilly - (2.6.9-1.681)
        root (hd0,4)
        kernel /vmlinuz-2.6.9-1.681_FC3 ro root=LABEL=/1 rhgb quiet
        initrd /initrd-2.6.9-1.681_FC3.img