[linux-lvm] Adding a disk to a VG gone bad - need help

[M. Matt Colgin]

Weird, I'm not totally following how/what happened, but it sounds like
you VG went from 1 PV to 3 (but maybe you started off with two). 
Hopefully you don't have some super important data on it. If you do,
there are some people with more knowledge than me, repost your
question with some more/updated information.

Each LVM command will write a "changelog" to the /etc/lvm/archive/*
directory with the state of the VG before/after the command was
issued. The best bet to undo the extend would be to issue a
vgcfgrestore with the file, before your vgextend.

It might be worth checking into the physical connections for your new
drive. The UUID is basically a uniq signature that is written to the
front of the drive/partition. If this UUID can not be found, then it's
possible the drive went bad or (most likely) the computer doesn't see
the drive anymore. Look at the cables, replace a cable, check out the
BIOS (make sure it's being detected), etc. Fixing a failed connection
is better than messing around with the LVM VG with a missing drive. If
you can get the drive to show up, then it would be a simple matter of
vgreduce.


On Fri, 25 Feb 2005 23:22:59 -0500, Jeff Macdonald
<macfisherman at gmail.com> wrote:
> Hi,
> I have one volume group and that is used as such:
> [root at jeff ~]# /usr/sbin/lvscan
>  ACTIVE            '/dev/VolGroup00/Root' [9.78 GB] inherit
>  ACTIVE            '/dev/VolGroup00/Home' [231.31 GB] inherit
>  ACTIVE            '/dev/VolGroup00/Swap' [320.00 MB] inherit
> 
> I added a whole disk to VolGroup00 like so:
> [root at jeff ~]# dd if=/dev/zero of=/dev/hde bs=512 count=1
> 1+0 records in
> 1+0 records out
> 
> created the physical volume:
> [root at jeff ~]# /usr/sbin/pvcreate /dev/hde
> 
> added it to the volume group:
> [root at jeff ~]# /usr/sbin/vgextend VolGroup00 /dev/hde
> 
> added 100G from the 150G drive to Home:
> [root at jeff ~]# /usr/sbin/lvextend -L+100G /dev/VolGroup00/Home
>  Extending logical volume Home to 331.31 GB
>  Logical volume Home successfully resized
> 
> At this point the docs suggest umounting the logical volume in order
> to resize the file system. So I decided I was going to reboot the
> computer and start it into single user mode. When doing that I'm
> greated with:
> 
> lvm exited abnormally!
> Couldn't find device with uuid <uuid>
> Couldn't find all physical volumes for volume group VolGroup00
> 
> So it seems that it can't find the new physical volume that I just
> added.  LVM is totally new to me, so any pointers would be great.
> Booting from CD into rescue mode I wasn't unable to get very far. I
> was able to run lvm and pvscan shows this interesting line:
> 
> PV /dev/hdf1 VG VolGroup00 lvm2 [ X GB / X GB free]
> PV /dev/hdg2 VG VolGroup00 lvm2 [ Y GB / Y GB free]
> PV unknown device VG VolGroup00 lvm2 [ Z GB / Z GB free]
> Total: 3 [ X GB ] / in use 3
> 
> It seems to be that vgreduce is what I want in order to start over,
> but running this in test mode with -t and --removemissing I see this
> worrying line:
> Removing LV Home from VG
> 
> and the line I want
> Removing PV with UUID {correct UUID}
> 
> Am I on the right track?
> 
> TIA
> 
> --
> Jeff Macdonald
> Ayer, MA
> 
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