(solved) Re: LVM: How to access a foreign volume group

[Xen]

Volker Wysk schreef op 13-12-2017 9:00:
> Am Sonntag, 10. Dezember 2017, 17:15:31 CET schrieb Volker Wysk:
>> You can either use a recovery system without encryption and without 
>> LVM, or rename its volume-group name.  You just need to do "cryptsetup 
>> open...", and the volume group of the system to be recovered will 
>> automatically emerge.
>> 
>> In case of two encrypted-LVM-volumes, you need to rename the vg name 
>> of the recovery system. You should *not* unlock the 
>> system-to-be-recovered yet.
>> 
>> Xen has made it clear how to rename the volume group:
>> 
>>    vgrename kubuntu-vg rescue-vg
>> 
>>    Then you must verify that /etc/fstab in the RESCUE system contains 
>> no
>>    references to "kubuntu-vg" and you might also have to rerun
>>    "update-grub" if you want to keep it this way.
>> 
> 
> I think, I've been happy too soon. The "update-grub" step doesn't
> work. I get some message "/dev/mapper/kubuntu--vg-root not found".
> After that, the rescue system is unbootable. (Only a test USB stick
> affected on my side.)

Oh sorry.

It is easy to forget those complexities...

So the system was booted with /dev/mapper/kubuntu--vg-root and now 
you've changed it and it can't find it anymore.

2 solutions that I can think of:

1) ln -s /dev/mapper/rescue--vg-root /dev/mapper/kubuntu--vg-root

2) use a Live DVD/stick to rename the VG first before you boot the 
rescue system.