[Xen-users] Re: Xen-users Digest, Vol 77, Issue 15

[Oliver Wilcock <oliver@xxxxxxx>]

I have used LVM inside a guest VM.

I don't understand your description though.
In particular I don't know what the following means: "Populated Xen 
guest image with DomO image."  You copied the bits from one LV to the 
new LV?
If you are trying to avoid installing the guest OS by copying the bits, 
or the file system from your Dom0, then you are going to need to explain 
to it were to find root.
If the LV that you created for your guest is /dev/Box1/root then the 
guest will need to use this name.
i.e. /dev/Box1/root

You will need to pass the entire disk into the guest.  Perhaps:

disk = [ 'phy:/dev/sdb,xvda,w' ]

To override the fstab and initrd expectations of the name of the root 
file system you can set the kernel parameter in your guest VM 
configuration.  Perhaps:
root=/dev/Box1/root

Oh, and if the guest is managing the volume group then the Dom0 can't. 
So before you mount the physical disk in the DomU you need to deactivate 
it in Dom0.
vgchange -a n /dev/Box1

If I've misunderstood and you are trying to create a nested LVM 
configuration I think you are going to run into trouble having two 
volume groups with the same name.
> volume.
   You copied the bits from the


On 2011-07-09 15:00, xen-users-request@xxxxxxxxxxxxxxxxxxx wrote:
> Date: Sat, 9 Jul 2011 22:27:41 +0530
> From: Prakhar Srivastava<prakhar.apj@xxxxxxxxx>
> Subject: [Xen-users] Cannot boot with LVM inside Xen DomU
> To:xen-users@xxxxxxxxxxxxxxxxxxx
> Message-ID:
>         <CAF+Dr+tBZg588Y+ZkkFs-nu8dLG_uJP=jQ6+fpLFKwcTjZ1KEw@xxxxxxxxxxxxxx>
> Content-Type: text/plain; charset="iso-8859-1"
>
> Hi,
> I have Xen 4.0 installation on Debian Squeeze. I am able to boot Xen guest
> based on physical partition but failing to boot Xen guest with LVM within
> DomU. To use LVM inside DomU, I took the following way:
> 1. Installed a basic debian squeeze system on a AMD64 box. Used the entire
> disk disk and configure LVM option to set root on LVM. The root is at
> /dev/Box1/root and swap is at /dev/Box1/swap_1
> 2. Installed Xen and Dom0 from repository.
> 3. Populated Xen guest image with DomO image.
>
> When I try to run the image, I get the error that the volume logical volume
> is not found. I have set root to /dev/mapper/root in Xen configuration
> volume.
> Is there anything I am missing. Has anyone used LVM inside Xen guest?
>
> Prakhar
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