[SGVLUG] Fedora Core 8 GRUB boot settings

[David Lawyer]

On Fri, Jan 04, 2008 at 10:43:29PM -0800, Matthew Campbell wrote:
> Good evening,
> 
> I have run across a simple problem that has had me stumped all day.
> Does anyone have a moment to help out?
> 
> Default FC8 install creates a GRUB config file:
>   root (hd0,0)
>   kernel /vmlinuz-2.6.23.1-42.fc8 ro root=/dev/sda2 rhgb quiet
> 
> When doing the vanilla installation and booting for the first time the
> kernel panics with:
> VFS: Cannot open root device "sda2" or unknown-block(0,0)
> Please append a correct "root=" boot option; here are the available partitions:
> Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
> 
> 
> I have spent hours sorting through many, many reports of this on
> Google.  It seems to span all makes of Linux and many kernel revs.  I
> tried all the 'this fixed it for me' suggestions to no avail.
> 
> It looks like the /boot partition was created properly,

What /boot partition?  Do you mean a partition which contains the OS?
There's no need for a separate boot partition except on PCs 12 years
old or so that have bios that can't boot from high disk sectors.

> but that
> either GRUB or the kernel can not find the third partition on the
> first disc where the root filesystem should live.  (The second
> partition is a 5Gig swap area.)

Isn't sda2 the 2nd partition?  Is it trying to mount the swap
partition as root?  Do you have root=/dev/sda3 (per lilo, or the
equivalent for grub) to tell the boot loader to use sda3 (the 3rd
partition) as root?  Looks like sda2 may be the compiled-in default
root.

> I saw a mention that if the root file system is formatted ext3 that a
> plain kernel would not be able to boot as it doesn't have a chance to
> load the ext3 module.

I don't think you need any ext3 module to mount an ext3 file system.
Just mount it as ext2 and it should work, but you will not have any of
the ext3 recovery features.

> The post also noted that using a ram disk can get around this
> problem.  Unfortunately it does not appear that the default
> installation includes a ram disk image....
> 
			David Lawyer