LVM2 Disk Layout (on-disk data-structures)

LVM2 Disk Layout (on-disk data-structures)

[David A. Barrett]

Does anyone know about where I can find
documentation of layout of information for
LVM2 on the disk?

I need to write code to parse the data
directly from the low-level disc image.

I need to do some data recovery operations
on multiple logical volumes in two volume groups
on two physical volumes (each a raid5).

Redhat's fedora 10 installation DVD overwrote
the partition table and a new lvm on every single
accessable device immediately after asking for
my keyboard type (without confirmation).

d dot barrett at asgard dot com.

LVM2 Disk Layout (on-disk data-structures)

[Jonathan Brassow]

It is text based.  You can see examples in /etc/lvm/archive or /etc/ 
lvm/backup.

  brassow

On Feb 12, 2009, at 11:22 AM, David A. Barrett wrote:

> Does anyone know about where I can find
> documentation of layout of information for
> LVM2 on the disk?
>
> I need to write code to parse the data
> directly from the low-level disc image.
>
> I need to do some data recovery operations
> on multiple logical volumes in two volume groups
> on two physical volumes (each a raid5).
>
> Redhat's fedora 10 installation DVD overwrote
> the partition table and a new lvm on every single
> accessable device immediately after asking for
> my keyboard type (without confirmation).
>
> d dot barrett at asgard dot com.
>
> --
> lvm-devel mailing list
> lvm-devel at redhat.com
> https://www.redhat.com/mailman/listinfo/lvm-devel

LVM2 Disk Layout (on-disk data-structures)

[Bryn M. Reeves]

David A. Barrett wrote:
> Does anyone know about where I can find documentation of layout of 
> information for LVM2 on the disk?
> 
> I need to write code to parse the data directly from the low-level 
> disc image.

There are better ways to do this. As Jon points out, the LVM2 metadata
is plain text. You can rip it out of the raw devices with dd if
necessary and then tidy it up in an editor.

You'll then want to look into vgcfgrestore.

If you didn't have a backup of your partition tables then you may want
to look at parted's rescue command.

> Redhat's fedora 10 installation DVD overwrote the partition table 
> and a new lvm on every single accessable device immediately after 
> asking for my keyboard type (without confirmation).

I'd file a bug if you can reproduce this.

Regards,
Bryn.