LVM and grub

[Mikkel L. Ellertson]

Gene Heskett wrote:
> On Monday 11 February 2008, Timothy Murphy wrote:
>> Mikkel L. Ellertson wrote:
>>> With /boot on its own partition, Grub does not need to access the
>>> root partition. This is good because Grub does not understand LVM.
>>> The thing you have to remember when using a separate /boot partition
>>> is that the paths that Grub uses do not start with /boot. You would
>>> use something like:
>>>
>>> title Fedora (2.6.23.14-115.fc8)
>>>          root (hd0,2)
>>>          kernel /vmlinuz-2.6.23.14-115.fc8 ro
>>> root=/dev/VolGroup00/LogVol00 rhgb quiet
>>>          initrd /initrd-2.6.23.14-115.fc8.img
>>>
>>> As far as Grub is concerned, your /boot directory is its root
>>> directory. This is what the root (hd0,2) is telling Grub.
>> My problem was that root=/dev/VolGroup00/... was not found,
>> since LVM was not active at at that point.
>> The boot started, but failed with "/dev/root not found".
>>
> Huh?  I've been booting with exactly that command line argument for quite some 
> time now.  Year (how old is FC6?) or more.  Perhaps your hd(0,2) is too far 
> into the disk and the bios is having problems?  One of the many reasons 
> the /boot partition is the first one here, and something in the back of my 
> mind says it cannot be a directory within an LVM, but must be a separate 
> partition.
> 
The message would be about the kernel or the initrd not being found, 
or Grub failing completely if the /boot partition was too far in. 
This sounds more like a problem with the initrd not having LVM 
support, or that root is not on VolGroup00/VolGroup00.

The output of "parted /dev/sda print" would help. So would the 
output of lvs.

According to the Grub info page, there is supposed to be a way to 
use Grub with /boot on a LVM, but you lose the ability to just edit 
the menu, or change kernels, without re-running grub-install. You 
don't use a stage 1.5 and Grub loses the ability to read the file 
system when booting. It preforms a lot like LILO does. I would not 
recommend it for the average user.

Mikkel
-- 

   Do not meddle in the affairs of dragons,
for thou art crunchy and taste good with Ketchup!

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