Re: GRUB advice needed.



On Sun, 29 Jan 2006 20:14:02 +0000, Charles Sullivan wrote:

> On Sun, 29 Jan 2006 12:04:07 -0700, Douglas Mayne wrote:
>
>> On Sun, 29 Jan 2006 17:45:07 +0000, Charles Sullivan wrote:
>>
>>> In the past I've partitioned my Linux i86 HDD like this:
>>> hda1 boot
>>> hda2 extended
>>> hda5 home (1)
>>> hda6 swap
>>> hda7 root (1)
>>> hda8 home (2)
>>> hda9 root (2)
>>>
>>> and moved back and forth between (1) and (2) when installing
>>> new releases in the same general family of Linuxes - e.g.,
>>> FC 1 -> FC 2 -> FC 3, etc.
>>>
<snip>
>>
>> Grub is a very flexible loader. After thinking about it just now, I
>> see that there are even more ways it can be used. My explanation covers
>> the basic case, though.
>
> Thanks for the detailed explanation Douglas, but I'm still a little
> unclear. Suppose I want to install two Linux distros on a new HDD

Do you mean, "new" as in "new" from the store? This drive is installed
in addition to any drives in your system. Or do you mean, "new" as in
"new format of the one existing disc"?

> and not use a boot partition. Do I end up with something like this:
> MBR -> grub stage1
> hda1 extended
> hda5 swap
> hda6 home (1)
> hda7 root (1)
> /boot
> kernel (1) and other boot files
> /grub
> grub stage 2 (1) files
> hda8 home (2)
> hda9 root (2)
> /boot
> kernel (2) and other boot files
> /grub
> grub stage 2 (2) files
>
> Do I still get the GRUB version selection menu (Fedora) when I reboot
> the system, or would I have to (Ugh!) boot from a floppy or CD each
> time? Or do the grub stage 2 files exist in only one of the root
> partitions?
>
> And if hda6 and 7 are later reformatted (same partitions, just cleared)
> and a new version of Linux installed, will GRUB still work or will I
> wipe out something critical?
>
> Or should I forget the whole thing and continue to use a boot partition?
> :-)
>
Note: comment inline.

As I implied, grub is a very flexible loader, and it is rare when the
fallback to floppy boot is required. The best course is just to plan in
advance what you intend to do, including the boot loader. Grub will
usually be able to accomodate your plan. Any time you spend learning
about the loader will pay off later.

Understanding what you're doing...

If you totally wipe out your partition with the "upper" stage files, then
you'll need to reinstall before Grub will work again. Note: my question
(above) and your answer will dictate how to proceed. Maybe, you should
make a grub floppy at this point so you will have a fallback position.

Specific advice...

One way to proceed is to keep your boot partition intact. When you
install new linux distributions, elect to install the grub loader on
_its_ root (linux) partition. That way, you can add a simple menu
entry on the "master" list on your boot partition's menu.lst. The new
entries on the "master" list would look something like this:

title Slackware Linux
rootnoverify (hd0,5)
chainloader +1

title OpenSuse Linux
rootnoverify (hd0,6)
chainloader +1

This approach saves copying the kernel and detailed menu.lst entry
necessary to load a specific distribution's kernel. You will have a
layered menu (menu upon menu), but in my opinion that is the simpler
choice.

Just keep your plan straight in your mind (or on paper). You are
more likely to have success that way.

--
Douglas Mayne
.