[linux-lvm] How to find out the location of PE's

[peter.bieshaar at gmail.com]

Sven,

thanks for this information. I will investigate the MetaData, on the second
sector, as you mentioned. Now I also can more easily search the code (using
the LVM2 and LABELONE strings). I tried but, it's a lot

Peter

2011/12/29 Sven Eschenberg <sven at whgl.uni-frankfurt.de>

> Assuming you used standard config when creating the LVM, you'll find PV
> metadata at the very beginning of the disk (an probably nowhere else).
>
> There is no such thing like per PE markers, all information is stored in
> the LVM header. Usually though there should be files in /etc holding the
> information of the PVs/VGs/LVs as backup - assuming the rest of the disk
> layout is still valid (i.e. PV on partition -> partition still exists)
>
> The LVM Metadata is in the second sector (usually) and you should see
> something like the string LVM2 and LABELONE (for LVM 2 metadata)
>
> I don't know of any detailed on disk format description (except the source
> probably).
>
> Regards
>
> -Sven
>
>
> On Wed, December 28, 2011 11:03, peter.bieshaar at gmail.com wrote:
> > Due to a hardware mistake (dvd and hdu as IDE-master ??) I lost complete
> > disk- and therefor lvm administration on SATA disks.
> > - In other words I cannot see the partition- or PV/VG and LV
> > administration.
> > - So, fdisk or (pv|vg|lv)display can't give information.
> >
> > lvm was initiated under ubuntu 11.04 or 10.10, a recent lvm2 version was
> > installed.
> >
> > On one disk I tried to create a partition (without creating a filesystem
> > of-course :) ) but no pv-information was shown, using pvdisplay. I didn't
> > dare to do this on my RAID1 (md) disks.
> > I can read the disks with strings and dd, and saw content of scripts and
> > documents. So the content/data is still on the disks.
> >
> > My chosen strategy to recover the LV's, is finding the PE's, pickthem
> > up and place them in a blob on another filesystem. So I can mount -o loop
> > that blob and restructure the disks.
> >
> > My problem now is how to find these information. The web gives a lot of
> > information how to setup, but almost none on technical issues like this.
> >
> > Can someone give me a hint on how this (the PE's) technically is being
> > organized (pointer -> pointer structures??) and where and how to search
> > these on the disk. So I can write a C-thingy to accomplish my strategy.
> If
> > someone already has something like this, or examples,
> >
> > --
> > Regards,
> >
> > Peter Bieshaar
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm at redhat.com
> > https://www.redhat.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm at redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
>



-- 
Regards/Met vriendelijke groet,

Peter Bieshaar
------------------------------------------
"FATAL ERROR" in large friendly letters
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