copying lvm with the same name

[Robin Laing]

Frank Cox wrote:
> One of my computers died and, of course, there is un-backed-up data on there
> that I want to recover if I can.  The hard drive seems to be in good shape so I
> took it out of the dead box and installed it on this computer (my main desktop
> machine.)
> 
> I have been doing a bunch of reading about logical volumes and some of what
> I've found is  self-contradictory, incomplete and stuff that I just don't
> really understand (yet.)  And, as you can imagine, since this is my main
> desktop machine I'm not terribly anxious to just start playing around with
> the lvm configuration without knowing what I'm doing.
> 
> Here are my findings so far:
> 
> [root at mutt ~]# pvscan
>   PV /dev/sdb2   VG VolGroup00   lvm2 [279.25 GB / 32.00 MB free]
>   PV /dev/sda2   VG VolGroup00   lvm2 [465.56 GB / 32.00 MB free]
>   Total: 2 [744.81 GB] / in use: 2 [744.81 GB] / in no VG: 0 [0   ]
> [root at mutt ~]# lvscan
>   ACTIVE            '/dev/VolGroup00/LogVol00' [277.28 GB] inherit
>   ACTIVE            '/dev/VolGroup00/LogVol01' [1.94 GB] inherit
> 
> It looks like the machine can see the second drive and the lvm that's on it
> /dev/sdb2, but it has the same VolGroup name as /dev/sda2.
> 
> What I would like to do is twofold:  First, and most importantly, I would like
> to mount it as-is so I can copy my data off of there.  Second, I would like to
> re-format it and add it to the storage capacity that I already have on this
> machine. Heck, if it's still a good drive I might as well put it to use.
> 
> So, how can I mount VolGroup00 that's on /dev/sdb2?  The vgchange command
> followed by a simple mount command looks like what I want to do, but what's the
> syntax?  As I said, I really don't want to bugger up my primary hard drive....
> 

I have read this thread and I wish I had seen something like it two 
years ago.  I had upgraded a system that used LVM and replaced two 
drives to increase the total available space.  It turned out that I had 
forgotten to backup a directory.  To late and rushing.

I wanted to install the removed drive to see if the directory was on 
that drive but it was part of the old group (generic name creation) and 
strange and wonderful problems started to crop up.  I never did get the 
drive mounted back then.

There needs to be a firm way of changing and editing LVM characteristics 
in these situations.

-- 
Robin Laing