[CentOS] Recovering LVM volumes

Fri Feb 4 00:53:40 UTC 2011
Gregory P.. Ennis <PoMec at pomec.net>

On Thu, 2011-02-03 at 16:28 +0530, Sanjay Arora wrote:
> Hello all
> 
> I have two sets of eIDE hard drives from earlier servers, one centos &
> one fedora. Both were LVM volumes with three or four physical disks,
> with ext3 fs. One disk, maybe even the boot one may even be missing,
> either from one or both sets and we do not know the disk order. I got
> these left from an earlier sysadmin who left the company & nobody know
> what's what.
> 
> I need to recover data so I need to backup each of the disks to a disk
> image file first, then find block-size/recover lvm metadata on the
> volume, mount the volume to my current server and recover whatever
> files can be recovered manually.
> 
> My question is:
> 
> - what switches to be used with dd in creating the image, so that I
> retain the lvm disk data, for future recovery, if I mess up the
> recovery job? Can you please give the actual command assuming disk is
> connected at /dev/sdb?
> 
> - How do I find the blocksize used by the disk & how do I get the
> meta-data and mount the disk to current lvm fs.
> 
> Request please give me step by step process. I am finding the howtos &
> examples on the net very daunting as most of them have co-issues of
> raid etc. Mine is a plain lvm spanning multiple disks.
> 
> I don't have expertise of this level & suddenly my boss is expecting
> me to perform a miracle.
man scanvg

-----------------------

I think Terry meant 'man vgscan', but I have not connected the dots to
be able to mount an lvm volume from a different machine either.

Greg