[CentOS] Where is the LVM config stored?

Tue Apr 3 13:27:27 UTC 2007
Ross S. W. Walker <rwalker at medallion.com>

> -----Original Message-----
> From: centos-bounces at centos.org 
> [mailto:centos-bounces at centos.org] On Behalf Of WipeOut
> Sent: Tuesday, April 03, 2007 6:40 AM
> To: CentOS mailing list
> Subject: [CentOS] Where is the LVM config stored?
> 
> Hi,
> 
> I am trying to migrate one of my systems to a VMware virtual 
> machine.. 
> The PC is an IDE drive using LVM and the virtual machine is a 
> SCSI drive 
> using ordinary partitions..
> 
> Basically I rsynced the entire filesystem from the physical to the 
> virtual machine and that seemed to work just fine.. I installed grub 
> onto the drive in the virtual machine and its booting fine..

What tool did you use to copy the host filesystem?

To what physical medium did you copy it to, vmware virtual disk file
or physical partition/logical volume?

> The problem comes when the new system trys to scan for the LVM setup 
> that was on the previous PC.. I thought it would scan the drive, and 
> seen that there are no LVM partitions and move on but it 
> doesn't it has 
> a kernel panic and flashes the cap lock and scroll lock LED's on the 
> keyboard.. Obviously somewhere its being told there should be an LVM 
> partition or its being told to scan hda rather than sda..

The LVM information is stored in the disk volume itself, there are
backup copies of the configuration routinely dumped to
/etc/lvm/backup, and archive copies of volume groups stored in
/etc/lvm/archive.

Make sure this "copy" of your physical host's drive isn't somehow
being accessed by the physical host at the same time as the virtual
host.

> I have checked the grub.conf and fstab files and they are all 
> right for 
> the new drive setup..
> 
> So where is the LVM config? How do I tell it there are now 
> LVM volumes 
> that need to be accessed?

If the PV headers were copied in the volume copy it should pick
those up on the pvscan, then vgscan will see any volume groups
defined within the PVs and lvscan should find any LVs within
the volume groups.

-Ross

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