Re: Building a boot disk with initrd

[Alvin Oga <aoga@mail.Linux-Consulting.com>]

On Wed, 15 Jun 2005, Diesis wrote:

> I'm stuck with this...
> I have a Debian Woody system with root on raid, and I wish to upgrade it.
> First of all, I wish to build a set of boot floppies that could be used 
> for booting and restart the complete system without troubles.

if it is truly a working raid .. it will boot from either disks...
and a 3rd boot media ( floppy ) is not needed ???

	- pull each disk out, one at a time and see if it boots and
	if it doesn't booot, you do NOT have properly configured raid

	- you can also use any arbitrary standalone boot cd from any
	and all vendors w/ raid support on the cd to boot into your raid

> I've tried
> 
> # mkboot /dev/fd0

that makes a boot floppy ...

boot floppies does not need initrd 

--------

standalone boot floppy does need initrd .. ( things that run in memory,
and you dont need a hard disk or cf or cdrom etc )

c ya
alvin
 
> Is there a smart and working way to build a two-three set disk like i 
> did with mkbootdisk under other systems ?

bad idea... you're making things 1000x more complicated than it needs
to be for your boot floppy

- in your case, you need to know if raid support is in the kernel or 
  as modules

	- if it is as modules .. you will have to decide, which problem
   	is easier to fix ... fix the kernel or fix your boot floppy
		- kernel is 100x easier to fix, by building raid into the
		kernel

- next simple way ..
    for lilo:

	change boot=/dev/hda   to boot=/dev/fd0  

    for grub:
	grub-install /dev/fd0


    for syslinux:
	you probably will need to create a bootable media first
	and go thru some additional steps


- if neither lilo nor grub works ... than you have to do more homework as
  follows:

        - understand when /boot is required and when it is not
                remove /boot and see if you "panic, why would i do that" 

                your boot floppy, boot cd, boot cf, etc will NOT have
                /boot
 
                the boot media ( fd, cd, cf, network ) just has MBR info
                and not /vmlinuz nor /initrd.gz

                /boot ( aka initrd for your problems ) will exists on say
                the hard disk

		build a minimal custom linux that runs in /dev/ram  
		and no other directories like /boot /bin /etc /sbin in
		anything other than in your initrd.gz

        - understand when initrd is required and when it is not
                initrd is NOT required if your kernel has everything
                built into it and is NOT modules that are required to boot

c ya
alvin