# Grub2 warning with LVM2

## binro

I have just been installing Grub2 following the wiki. All went well until I ran the mkconfig:

```

# grub2-mkconfig -o /boot/grub2/grub.cfg

Generating grub.cfg ...

/usr/sbin/grub2-probe: warning: Couldn't find physical volume `pv1'. Some modules may be missing from core image..

/usr/sbin/grub2-probe: warning: Couldn't find physical volume `pv1'. Some modules may be missing from core image..

/usr/sbin/grub2-probe: warning: Couldn't find physical volume `pv1'. Some modules may be missing from core image..

/usr/sbin/grub2-probe: warning: Couldn't find physical volume `pv1'. Some modules may be missing from core image..

Found linux image: /boot/vmlinuz-3.4.0-gentoo

Found initrd image: /boot/initrd-3.4.0-gentoo

Found linux image: /boot/vmlinuz-3.3.2-gentoo

Found initrd image: /boot/initrd-3.3.2-gentoo

done

```

I have no volume pv1:

```

# pvs

  PV         VG   Fmt  Attr PSize   PFree 

  /dev/sda3  vg00 lvm2 a--  213.79g 59.79g

  /dev/sdb4  vg00 lvm2 a--  170.73g 84.73g

```

The generated grub.cfg looks OK, AFAICT. So is this a serious problem?

TIA

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## ShadowCat8

Greetings,

What are the USE flags you are using with GRUB2?  Do you have it compiled with "device-mapper" and "mount"?

And, do you have the LVM modules built into your initrd?

HTH.  Let us know.

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## rjtupas

Do you need grub 2 compiled with device-mapper support if your MBR (root) is NOT on a LVM partition? I currently have root on a normal partition, but /usr, /var ... on LVM partitions. I'm experiencing e2fsck errors with /usr.

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## binro

 *ShadowCat8 wrote:*   

> 
> 
> What are the USE flags you are using with GRUB2?  Do you have it compiled with "device-mapper" and "mount"?
> 
> And, do you have the LVM modules built into your initrd?

 

Grub2 was compiled with "device-mapper". I recompiled it with "mount" but it made no difference. Yes, LVM is built into my initrd. I also specified

```

GRUB_PRELOAD_MODULES=lvm

```

in /etc/default/grub.

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