Re: [gentoo-user] Booting Gentoo from USB stick

[David Relson]

On Fri, 10 Sep 2010 11:05:12 +0200
J. Roeleveld wrote:

> On Friday 10 September 2010 10:43:30 Jake Moe wrote:
> >   On 10/09/2010 5:27 PM, Maciej Grela wrote:
> > > 2010/9/10 Jake Moe<jakesaddress@×××××.com>:
> > >>   Hello all,
> > >>
> > >> I've been thinking about creating a Gentoo USB stick for install
> > >> and rescue purposes (and, of course, just to see if I could).
> > >> I've mostly followed the Gentoo handbook (I used a single 4GB
> > >> partition for the whole system, and no swap).  I've used
> > >> genkernel for the kernel (so I can have a multi-system capable
> > >> kernel).  I've gotten GRUB installed and working.  My problem
> > >> comes in after what I believe is the init process:
> > >>
> > >>
> > >> Gentoo Linux; http://www.gentoo.org
> > >>
> > >>   Copyright 1999-2009 Gentoo Foundation; Distributed under the
> > >> GPLv2
> > >>
> > >> Press I to enter interactive boot mode
> > >>
> > >>   * Mounting proc
> > >> at /proc ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Mounting sysfs
> > >> at /sys ... [
> > >>
> > >> ok ]
> > >>
> > >>   *
> > >> Mounting /dev ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Starting
> > >> udevd ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Populating /dev with existing devices through
> > >> uevents ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Waiting for uevents to be
> > >> processed ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Mounting devpts
> > >> at /dev/pts ... [
> > >>
> > >> ok ]
> > >>
> > >>   * Checking root filesystem ...
> > >>
> > >> fsck.ext2: No such file or directory while trying to
> > >> open /dev/sda1 /dev/sda1:
> > >> The superblock could not be read or does not describe a correct
> > >> ext2 filesystem.  If the device is valid and it really contains
> > >> an ext2 filesystem (and not swap or ufs or something else), then
> > >> the superblock
> > >>
> > >> is corrupt, and you might try running e2fsck with an alternate
> superblock:
> > >>     e2fsck -b 8193<device>
> > >>
> > >>   * Filesystem couldn't be
> > >> fixed :( [
> > >>
> > >> !! ]
> > >> Give root password for maintenance
> > >> (or type Control-D to continue):
> > >>
> > >>
> > >> If I give the root password, I can find no /dev/sda1.  However,
> > >> mount shows /dev/sda1 on /, and there *is* a /sys/block/sda
> > >> folders, with a sda1 folder in that as well.  It's almost like
> > >> it had /dev/sda1, but then lost it somehow.
> > >>
> > >> Does anyone have any idea what's going on here?  Any help would
> > >> be appreciated.
> > >
> > > Have you seen http://www.sysresccd.org/Main_Page ? It's based on
> > > Gentoo, you could check what they did to boot from a usb stick.
> > >
> > > Br,
> > > Maciej Grela
> >
> > Excellent, thanks for that, I hadn't found it in my previous
> > searches. I'll have a look there.
> >
> > Jake Moe
>
> Had a similar issue a while ago when I was playing around with this
> myself.
>
> Take a look at the linux boot parameters.
>
> The 'theoretical' part is: You need to let the kernel initialize the
> USB-stick before trying to access it. (This can take some time)
>
> There is a delay-option, just can't remember the proper name off-hand.
>
> --
> Joost

I've got USB booting working in a syslinux environment.  A delay of 12
seconds is working for me.  The syslinux.cfg stanza I use is:

LABEL usb
KERNEL linux
APPEND rootdelay=12 root=/dev/sda2

HTH,

David