On Wed, Jun 30, 2010 at 2:57 PM, Nathan Coulson <conat...@gmail.com> wrote:
> On Wed, Jun 30, 2010 at 2:10 PM, Andrew Benton <b3n...@gmail.com> wrote:
>> On 30/06/10 19:33, Stuart Stegall wrote:
>>>
>>> Seems like it should be the simplest way possible. Personally I don't
>>> like the grub-mkconfig - has failed to work for me a few times, and I
>>> believe it does that due to my host system.
>>>
>> grub-mkconfig has never worked for me as I use btrfs for my root partition
>>
>>> Seems like a much more simple approach of:
>>>
>>> # cat<<EOF> /boot/grub/grub.cfg
>>> set timeout=10
>>> set default=0
>>> menuentry "LFS x.x" {
>>> set root=(hd0,1)
>>> linux /vmlinuz root=/dev/sda2
>>> }
>>> EOF
>>>
>>> Would be better.
>>>
>> I agree. I've always written grub.cfg by hand from examples found with
>> google.
>>
>> Andy
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> Boot Process:
> Grub2 runs.
>
> set root=, or search to set the root partition for grub. AFAIK, this
> is only useful for saying where / goes. (ex:/ I used
> (hd1,1)/boot/lfskernel, and it still worked, without setting root to
> anything).
>
> Loads the kernel by using /boot/lfskernel (if root is set), or (hd1,1)
> completely ignoring whatever root is set to.
>
> Linux loads, and the grub root is lost. AFAIK, linux has no way of
> obtaining this information.
>
> Linux looks for the root filesystem. These are the options I know
> root=/dev/sda1 - Loads this partition
> root not set - Load the partition set within the kernel image (Set
> w/ rdev if I recall)
> linux then runs /sbin/init [or whatever init= on the commandline]
>
> (an alternative way, is if linux loads a initrd/initramfs. Then you
> can use a few shell scripts to find the root instead. This is how
> distributions make root=UUID=abcdefg or root=LABEL=os work).
>
>
>
> So, regardless if you search or not, or set root manually, this has no
> effect once the kernel boots. You either need root=/dev/sda1, or you
> need to use rdev (used to be in util-linux) to set the root. I
> believe when you compile the kernel, rdev is set automatically to
> whatever / is.
As for fstab, it can only be read 'after' the root partition was
mounted. At that point, it is too late in the equation.
--
Nathan Coulson (conathan)
------
Location: Brittish Columbia, Canada
Timezone: PST (-8)
Webpage: http://www.nathancoulson.com
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