[linux-lvm] Renaming Loopback 'Mounted' Volume Group

Tod tod at stthomasepc.org
Tue Nov 27 02:58:59 UTC 2007

Bryn M. Reeves wrote:
> Hash: SHA1
> Tod wrote:
>> Please take a look at this old thread first ...
>> http://linux.derkeiler.com/Mailing-Lists/Fedora/2007-02/msg02237.html
>> This was back in February and I'm just now trying to get back into
>> recovery mode.  I've mounted the image like so:
>> /sbin/losetup /dev/loop0 ./recover.img
>> /sbin/kpartx -lv /dev/loop0
>> /sbin/kpartx -av /dev/loop0
>> This gives me /dev/mapper/loop0p1, and /dev/mapper/loop0p2 which seeoupNew
>>  be my original boot drive and VolGroup00.  When I do an lvscan I get: 
>> WARNING: Duplicate VG name VolGroup00: Existing
>> Vmi02d-0hr7-7NVb-vYZi-1fbD-E9n5-ixWu0a (created here) takes precedence
>> over D7avZX-pVCb-ibTN-tyvs-7Q62-rzR9-tquBi9
> See the steps I posted last Friday, with some corrections/improvements
> from Alasdair:
> https://www.redhat.com/archives/linux-lvm/2007-November/msg00039.html
> https://www.redhat.com/archives/linux-lvm/2007-November/msg00040.html

Thanks Bryn.

Before I make a mess I'd like to recite my steps to see if they seem 
reasonable to you.  I've made a little progress (I think) since the post 
above that might allow me to streamline things.

Of the two 'partitions' on my disk image, only the LVM one has content 
that is important to me and I already know its offset.  Combining both 
your's and Alasdair's steps:

1.  /sbin/losetup /dev/loop0 ./recover.img
2.  /sbin/losetup -o 106928640 /dev/loop1 /dev/loop0
3.  Running pvscan shows me the loopback PV, and gives me expected 
warning regarding the duplicate VG name
4.  Setup temp LVM dir and set LVM_SYSTEM_DIR to point to it
5.  Copy lvm.conf to that dir and apply filter = [ "r|/dev/loop[01]|", 
"a|.*|" ] to it
6.  Clone the PV -> dd if=/dev/loop1 of=/dev/loop2
7.  pvchange --uuid /dev/loop2
8.  vgchange --uuid VolGroup00
9.  vgrename VolGroup00 VolGroupNew
10. Discard LVM_SYSTEM_DIR env var & directory
11. Activate new VG ->  vgchange -ay VolGroupNew

Does this look right?  The one concern I had was step 8 since both my 
currently active VG and the one from the disk image share the same name. 
  I'm guessing steps 4 and 5 will prevent that?

Thanks for all of your help.

- Tod

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