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