Re: [gentoo-user] grub and what happens exactly when booting.

[Alan McKinnon]

On Thu, 15 Sep 2011 20:49:02 -0500
Dale <rdalek1967@×××××.com> wrote:

> OK.  The Chief Idiot is going to experiment some.  You ALL know what
> this means right?  Yep, I'm about to really make a mess of things so
> here comes some questions.  This is a result of the /usr and udev
> crap. So, go to -dev and blame them, not me.  ;-)

Uh-oh!  :-)

>
> OK.  I have three drives in my rig.  One is for data files, mounted
> on /data ironically, and has nothing to do with the OS.  So, for that
> reason I'm going to leave it out of this.  So, I now have two drives
> in my rig that are about to be OS related.  sda is a 160Gb and sdb is
> a 250Gb.  I'm going to leave the first one, sda, as is and will use
> sdb for testing.  Before I start, I want to sort of get my brain
> wrapped back around this.  It has been a LONG time since I dual
> booted Linux and that was only for a month or so.  I have grub
> installed on the MBR of sda.  My boot partition is on sda1 like most
> likely 99% of the rest of you and it will stay there even after all
> this is done.  I got /boot from the old handbook days.  When I put my
> new install on sdb, with this new initramfs thingy and quite possibly
> LVM, do I leave grub on sda's MBR and just point to sdb for the
> kernel and init thingy and all will be well?

The basic idea is you set the boot drive in the bios and which runs grub
from that drive's mbr. When you installed that grub you hard-coded it
to know where to find it's grub.conf.

You can use the existing grub and it's config files just fine. Add a
new entry for your new stuff on sdb - grub will reference that drive as
(hd1) in grub.conf - and configure the root, kernel and initrd
settings appropriately.

If I were you I'd install grub to the mbr on sdb as well. If you happen
to switch sda and sdb around, you'll still have code to boot from on
the new first drive and not need to change the boot drive settings in
the bios. It's not a necessity, just a convenience.



>
> If this all works out, I will be moving everything from sdb to sda
> anyway.  My plan is to get them both bootable, then use one to copy
> to another after I have learned a bit about this mess.  I haven't got
> that far yet but wanting to figure this init thingy out before I'm
> forced to which will only make it taste even worse.
>
> What I am reading so far:
>
> http://en.gentoo-wiki.com/wiki/Initramfs
>
> I did a google search and found some others boot this is more Gentoo
> oriented.  So, anything wrong with this as a guide?  Pointers to
> others if they are better would be great.
>
> Here starts a learning process.  It could get bumpy.  lol
>
> Dale
>
> :-)  :-)
>



-- 
Alan McKinnnon
alan.mckinnon@×××××.com