If you just need to transfer the data to the new installation, attach the
external drive to a different machine and rsync it. Boot with live media
if you have the same problem on the other machine.

fsr


On 08/14/2015 09:13 PM, Hendrik Boom wrote:
> On Sat, Aug 15, 2015 at 12:41:06PM +1200, Daniel Reurich wrote:
>> On 15/08/15 12:24, Hendrik Boom wrote:
>>> I tried plugging a external hard drive into my newly installed Devuan
>>> system, and immediately ran into a problem: It seems the volume group
>>> name used on that drive is the same as the one on my devuan system.
>>> Not that surprising; thee external drive contains the Debian system I'm
>>> migrating away from.
>>>
>>> lvdisplay tells me:
>>>
>>> root@notlookedfor:~# lvdisplay
>>> WARNING: Duplicate VG name VG1: Existing
>>> zXs7iy-ukO4-ecrC-B1ag-wQkA-6L4K-YKyKRV (created here) takes precedence
>>> over P4Ggic-hQS6-b82V-zUj6-a0eu-dA3z-5mIkOH
>>> WARNING: Duplicate VG name VG1: Existing
>>> P4Ggic-hQS6-b82V-zUj6-a0eu-dA3z-5mIkOH (created here) takes precedence
>>> over zXs7iy-ukO4-ecrC-B1ag-wQkA-6L4K-YKyKRV
>>> WARNING: Duplicate VG name VG1: Existing
>>> zXs7iy-ukO4-ecrC-B1ag-wQkA-6L4K-YKyKRV (created here) takes precedence
>>> over P4Ggic-hQS6-b82V-zUj6-a0eu-dA3z-5mIkOH
>>>
>>>
>>> How do I go about mounting its LVM partitions without screing everything
>>> up? Can I just ignore the name conflict and mount by UUID? And are the
>>> UUIDs in the error message the ones I need for this?
>>
>>>
>>> Or is there some way to rename VG1 to something else? Some way that
>>> will take care of all the corner cases? There's a command vgimportclone
>>> that seems to be for this, but ... it says it also changes the UUID's,
>>> which are *not* duplicates, and it just might be that another use of
>>> this external disk might rely on those particulat UUIDs.
>>
>> vgrename supports identifying the volumegroup by UUID - so try:
>> vgrename <UUID> <new vg name>
>
> I'll have to be careful with that -- the lvdisplay message suggests that
> it has assigned new UUID's for that VG1 at least three times. Does
> that mean the disk has been rewritten? Or does LVM lie to itself as a
> kludge to prevent catastrophe?
>
>>
>> If your changing the old vg and not booting it again, then fine, but
>> if you want to change either the running systems VG name (or keep
>> the old system bootable) you'll need to fix the relevant fstab and
>> grub(2) configuration to match the changes.
>
> Yes. I hope that's all.
>
> It may ne simples to rename the VG1 in the devuan system -- if something
> goes wrong, I don't yet have enough effort invested to make a fresh
> install problematic.
>
>>>
>>> It's just possible that the LVM partition names will also have a
>>> conflict.
>>
>> shouldn't be a problem once you fix the volume group name conflict.
>
> Yes, their full names do end up containing the VG name, don't they?
>
>>

>> Cheers,
>>     Daniel.

>
> Thank you. You've been very helpful.
>
>>
>> --
>> Daniel Reurich
>> Centurion Computer Technology (2005) Ltd.
>> 021 797 722
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