LVM and grub

[Timothy Murphy]

Mikkel L. Ellertson wrote:

>> I set up an LVM partitioning scheme on one computer,
>> with /boot on /dev/sda3 outside LVM .
>> But grub could not access / because LVM was not activated.
>> This made me wonder:
>> 
>> 1. Is there any way of asking grub to activate LVM
>> (eg run "vchange -a y") before it looks for the / partition?
>> 
>> 2. Is there any argument one could add to the kernel line
>> to the same effect?
>> 
>> In the end I deleted the LVM, and used ordinary partitions,
>> so the question is purely academic.
>> 
> 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".


-- 
Timothy Murphy  
e-mail (<80k only): tim /at/ birdsnest.maths.tcd.ie
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s-mail: School of Mathematics, Trinity College, Dublin 2, Ireland