partition tip ?

[Michal Jaegermann]

On Tue, Jan 29, 2008 at 04:24:44PM -0800, Arne Chr. Jorgensen wrote:
> 
> Michal Jaegermann wrote:
> >
> > If you have multiple Linux installations on one host then it is a
> > very good idea to have one "master boot partition",
> 
> This is exactly some of the idea I had in mind.

Good! :-)

> How to do it, is the difficult question.

Nah!  Assuming that you are starting with a "clean slate" leave some
small "master boot partition" and install grub for the first
installation in its "boot partition".  That is not bootable yet
although it will have correct "secondary loader" and its menu
written by anaconda.

So boot now "rescue" from an installation media, install grub on MBR
and write yourself its boot menu which will look roughly like what
you propose.

Or you can make your first installation to boot from MBR and after
you booted create a "secondary loader setup".  Probably the first
method is harder to screw up due to minor typos.
> 
> Now, let me see if I understood what Michal wrote:
> 
> 1. a "master boot partition": - would this simply be GRUB ?

Right; only GRUB is a bit more that its boot menu. :-)
Type:

  info grub Installation 'Installing GRUB natively'

and read that if you have not done that already.

> - with entries like
> 
> 
>  title LINUX 1st
>         rootnoverify (hd0,0)
>         chainloader +1
>  title LINUX 2nd
>         rootnoverify (hd0,0)
>         chainloader +1

Close, but you want things like 'rootnoverify (hd0,3)' and
'rootnoverify (hd1,5)' and similar.   You are switching root to a
boot partition of a distro you want to boot so these will be all
different.

> 2. "with boot sectors installed on partitions, for all instances"
> - hmm... ? ( perhaps I am a bit slow right now.. you would have
> to create some primary partions ?

No, you do not have to chainload from a primary partition.  A
"logical" on "extended" partition is fine; although GRUB needs to
find it so it cannot be hidden behind LVM.  All other partitions for
that installation can be.

> and then let the install program
> use automatic LVM ? ...create 2 ?  a root '/' and a boot '/boot'..?

"Automatic" does not work the best as it will try to grab all your
disk space.  Just create some partitons you need, with what is
mounted on /boot to be a "real one" and tell installer to put grub
on the first sector of your boot partitions _for that distro_.  You
also do not have to have separate /boot and / either but if you need
to more some storage around then LVM can turn out to be handy.

Swap space can be common for everything as long as you do not plan
to "hibernate", boot some other distro, and after that to try to
"wake up" the first one.  Such stunt will likely end up with a file
system damage (although it will work, provided it works without
booting something else, if you do not share swap).

   Michal