Grub Configuration Help

[Kevin Freeman]

On Mon, 2004-11-15 at 18:59 -0600, Chris LaForce wrote:
> Hello,
>    I've just downloaded Fedora Core 3 and installed it on a sencond hard
> drive(/dev/hdf). My first hard drive(/dev/hde) has Fedora Core 2 on
> it.  Here is the grub.conf file:
>  title Fedora Core 2 (2.6.8-1.521)
>  root (hd0,0)
>  kernel /vmlinuz-2.6.8-1.521 ro root=LABEL=/ rhgb quiet
>  initrd /initrd-2.6.8-1.521.img
> 
> What do I need to add to it to be able to also boot to the FC3
> OS?  Here's what I tried last time:
> 
> title Fedora Core 3 (2.6.9-1.667)
> root (hd1,0)
> kernel /vmlinuz-2.6.9-1.667 ro root=/dev/hdf2
> initrd /initrd-2.6.9-1.667.img
> 
> I can't find and example of multiple hard drive boots with two linux
> OS's.
> Thanks,

What you posted looks like it should work, at least until the next time
you upgrade the FC3 kernel.  Looking at the FC3 entry, its boot
partition should be on /dev/hdf1 and its root on /dev/hdf2.  /dev/hdf1
(FC3) should have a directory structure similar to /dev/hde1.  You
should also verify that /boot/grub/device.map on /dev/hde1 (FC2) maps
hd1 to /dev/hdf.

Did you manually enter the FC3 portion in FC2's /boot/grub/grub.conf?
If not, then FC2 and FC3 are actually using the same /boot partition,
and FC3's /boot is actually empty.  If this is the case, you should also
install grub on /dev/hdf1.  Then modify FC2's /etc/grub/grub.conf so
that the FC3 entry looks like:
title Fedora Core 3
        root (hd1,0)
        chainloader +1

This way both FC2 and FC3 have independent /boot partitions.  You should
also copy FC2's /boot to FC3's /boot partition so that you have working
FC3 /boot.  After you have booted FC3, you should clean out the FC2
kernel info from FC3 /boot.  You could also add an entry such as:
title Fedora Core 2
        root (hd0,0)
        chainloader +1
to give you the option of returning to FC2 if you change your mind
before booting.

If instead you would rather share /boot between both installs, then you
need to modify the "root" portion of the FC3 stanza to point to hd0.  I
would not recommend this option if you ever intend to have both installs
using the same OS version, _OR_ if you ever upgrade either install to a
later Fedora release.  Redhat/Fedora upgrades tend to blindly remove any
kernels that it deems "obsolete."

Kevin Freeman