[linux-lvm] Clone disk with LVM

[linux-lvm] Clone disk with LVM

[Ryan Nelson]

I had a Linux system using LVM for / (root) that was going away for 
field tests and the users of the system wanted to have a couple hot 
spares of the drives.  Using dd I replicated the disk to two diffrent 
drives.  One drive stored away and the other drive was going to be in 
the system being rsync'd nightly so that it would have the freshest data 
on it.

Because of the dd the LVM had the same names and UUIDs for the vg and 
lg.  I was able to change the names however I wasn't successful in 
change the UUIDs.  It didn't even look like there was an option to 
change the UUIDs for the lv. 

What would have been the correct way to achieve a setup like this with 
LVM?  I would assume a mirroring of some sort although I don't know what 
would be involved for the user if the drive did die and they needed to 
use the second drive.

Thanks
Ryan

Re: [linux-lvm] Clone disk with LVM

[Nix]

On 2 Jul 2007, Ryan Nelson spake thusly:
> Because of the dd the LVM had the same names and UUIDs for the vg and lg.  I was able to change the names however I wasn't
> successful in change the UUIDs.  It didn't even look like there was an option to change the UUIDs for the lv.

vgcfgbackup, edit the backup, edit the ids in the logical_volumes
sections, check your work carefully, and vgcfgrestore?

(One very nice thing about LVM2 is that all the metadata is textual...)

-- 
`... in the sense that dragons logically follow evolution so they would
 be able to wield metal.' --- Kenneth Eng's colourless green ideas sleep
 furiously

Re: [linux-lvm] Clone disk with LVM

[Alasdair G Kergon]

On Mon, Jul 02, 2007 at 02:51:52PM -0700, Ryan Nelson wrote:
> It didn't even look like there was an option to 
> change the UUIDs for the lv. 
 
You don't need to.  LV UUIDs are always qualified by the VG UUID.
Create an LVM2 installation using LVM1 metadata with more than one VG
with at least one LV in each and you'll see duplicate LV UUIDs.

Alasdair
-- 
agk@redhat.com