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Subject: Re: [linux-lvm] Exposing the same VG from two different disks
From: "Bryn M. Reeves" <bmr@redhat.com>
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Date: Fri, 05 Jun 2009 14:50:21 +0100
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On Fri, 2009-06-05 at 15:18 +0200, liam@landv.org.uk wrote:
> Hi,
> 
> I'm not sure if what I'm trying to do is possible or not but hopefully
>  someone out there can help!!
> 
> I have a volume group which consists of a LUN (/dev/emcpowerv1) in an
>  EMC cabinet. To backup up the disk I use EMC technology to synchronise
>  a second LUN (/dev/emcpoweraf1) with the first, when the
>  synchronisation is complete I then break the connection. At this point
>  I have two identical volume groups exposed to the same host. What I
>  would like to do is rename the second volume group and mount its
>  logical volumes. However I can't because (understandably) LVM doesn't
>  like having two identical volume groups so when I issue pvchange -u I
>  get...
> 
> 
> # pvchange -u /dev/emcpoweraf1
>   Found duplicate PV dXiYI6nVqu8UpXO2mlaWiKKPKSBPrRbn: using /dev/emcpowerv1 not /dev/emcpoweraf1
>   get_pv_from_vg_by_id: vg_read failed to read VG !
>   /dev/emcpowerv1: write failed after 0 of 4096 at 4096: Operation not permitted
>   pv_write with new uuid failed for /dev/emcpowerv1.
>   0 physical volumes changed / 1 physical volume not changed
> 
> Notice I issue the command against /dev/emcpoweraf1 but it complains about writing to /dev/emcpowerv1.

Take a look at the vgimportclone script posted to the lvm-devel list
last month:

http://www.redhat.com/archives/lvm-devel/2009-May/msg00130.html

Regards,
Bryn.