LVM partitions on ax external USB HD

[Jim Cornette]

Antonio Montagnani wrote:
> Jim Cornette wrote / ha scritto on /il 10/04/2005 14:46:
> 
>>
>>>
>>
>> From an earlier posting someone suggested to run the following 
>> commands to activate and later deactivate LVM volumes in rescue mode. 
>> I used these commands on an external USB drive to get at data from a 
>> previous installation and it worked. You might be able to get at your 
>> data in this way.
>> Jim
>>
>> Excerpt from earlier help.
>> Once booted into text-mode rescue, invoke the following commands:
>>
>> lvm lvscan
>> lvm vgchange -ay
>>
>> This will scan for all LVM volumes and then will make them active and 
>> accessible.
>>
>> lvm vgchange -an
>>
>> will deactivate them all.
>>
> Tnx Jim
> 
> But if I am a standard user with my machine running (with LVM on it), 
> and I connect an external LVM hard disk,how do I activate that 
> volumes??? not in rescue mode I mean.
> I suppose that if  I play with lvm vgchange -an I will break everything 
> also on the running system. Is it true??
> 

It didn't break my running system when I tried this. What I did was 
mount the drive as root and pull all of my regular user stuff off of the 
  /home/user directory as a user with the same name. I was interested in 
the items from my user primarily, but I did also pull in some stuff from 
/etc as root.

What you do is to create a new directory under mnt for the / partition 
of the old drive, say /mnt/oldroot and if you have a seperate home lvm, 
which I did not, I had only one big / partiton.

After you get the volume activated, you will notice some additional 
mounting device called something like /dev/vol00/grp00 or some cryptic 
line that lvm uses. I am running reular partitions and do not have the 
lvm volume at hand, so I don't recall the exact device name for a lvm.

Then you mount the volume with the below command and you should see the 
directories in /mnt/oldroot and can get at the information.
mount /dev/cryptic-line /mnt/oldroot and you should be set.

Doing this as a regular user might not work. Booting from rescue mode, 
activating the volumegroup, making a mount point and then chroot to the 
mounted lvm should give you somewhat of whatever the USB drive had for 
an OS.

Jim

-- 
Johnson's law:
	Systems resemble the organizations that create them.