Set an LVM volume as default root device

Set an LVM volume as default root device

[Aesir]

Hi everyone,

while discovering the beauties of grub2 I'm trying to get a working setup with /boot partition on LVM. Unfortunately until now to boot this system I had to set root device and prefix "by hand" from the rescue shell. In fact, while the working values should be

root (vg0-boot)
prefix (vg0-boot)/grub

the ones that grub2 uses by default are

root (hd0)
prefix (hd0)/grub

I haven't figured out yet how to change that default value, even reading grub-setup help I couldn't find it out. I would be really pleased if someone could help me.

Sorry if this is a silly question, hope for your comprehension :-)

Thanks!

-- 
Maurizio Longari <aesir.ml@gmail.com>

Re: Set an LVM volume as default root device

[Robert Millan]

On Sat, Feb 28, 2009 at 06:55:09PM +0100, Aesir wrote:
> Hi everyone,
> 
> while discovering the beauties of grub2 I'm trying to get a working setup with /boot partition on LVM. Unfortunately until now to boot this system I had to set root device and prefix "by hand" from the rescue shell. In fact, while the working values should be
> 
> root (vg0-boot)
> prefix (vg0-boot)/grub
> 
> the ones that grub2 uses by default are
> 
> root (hd0)
> prefix (hd0)/grub
> 
> I haven't figured out yet how to change that default value, even reading grub-setup help I couldn't find it out. I would be really pleased if someone could help me.
> 
> Sorry if this is a silly question, hope for your comprehension :-)

grub-install / grub-mkconfig should already DTRT.  Are you using those to
install and generate grub.cfg ?

-- 
Robert Millan

  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
  how) you may access your data; but nobody's threatening your freedom: we
  still allow you to remove your data and not access it at all."

Re: Set an LVM volume as default root device

[Aesir]

On Wed, 4 Mar 2009 22:05:38 +0100
Robert Millan <rmh@aybabtu.com> wrote:

> On Sat, Feb 28, 2009 at 06:55:09PM +0100, Aesir wrote:
> > Hi everyone,
> > 
> > while discovering the beauties of grub2 I'm trying to get a working setup with /boot partition on LVM. Unfortunately until now to boot this system I had to set root device and prefix "by hand" from the rescue shell. In fact, while the working values should be
> > 
> > root (vg0-boot)
> > prefix (vg0-boot)/grub
> > 
> > the ones that grub2 uses by default are
> > 
> > root (hd0)
> > prefix (hd0)/grub
> > 
> > I haven't figured out yet how to change that default value, even reading grub-setup help I couldn't find it out. I would be really pleased if someone could help me.
> > 
> > Sorry if this is a silly question, hope for your comprehension :-)
> 
> grub-install / grub-mkconfig should already DTRT.  Are you using those to
> install and generate grub.cfg ?
> 
> -- 
> Robert Millan
> 
>   The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
>   how) you may access your data; but nobody's threatening your freedom: we
>   still allow you to remove your data and not access it at all."
> 
> 
> _______________________________________________
> Grub-devel mailing list
> Grub-devel@gnu.org
> http://lists.gnu.org/mailman/listinfo/grub-devel

Thanks for the reply.
I realized what the problem was.

The commands I was using were:

grub-mkimage --output=/boot/grub/core.img ext2 _chain pc gpt biosdisk lvm --prefix=/grub

and

grub-setup --root-device='(vg0-boot)' /dev/sda

Obviously my fault was to indicate only the relative path in the --prefix option instead of '(vg0-boot)/grub'. I mistakenly tought that the --root-device option in grub-setup served for that purpose.

Now everything is perfectly working, 
Thanks again.

-- 
Maurizio Longari