[linux-lvm] Volume group not found on restart [resent]

Heinz J . Mauelshagen mauelshagen at sistina.com
Thu May 23 12:15:02 UTC 2002

On Wed, May 22, 2002 at 03:04:51PM -0400, Murthy Kambhampaty wrote:
> Heinz, 
> > 
> > Well, that shouldn't have happened in case "vgreduce db_vol 
> > /dev/sda" went ok
> > back then.
> > Do you have any memory of failure messages for that one?
> There weren't really any failure messages. I was just trying to go through
> the steps of removing the PV from the VG, then "remove the PV", then
> reformat the drive/yank it. I had a similar problem on another box, where
> I'd set up a VG create an LV, use if for a while then try to scrap the
> system because I needed to redeploy my HDDs. Once the vgreduce/vgremove step
> was completed, I'd do a PV scan and it would still list the removed PV as
> belonging to the VG or list the size of the VG at the old size. I'd reboot
> and do a pvscan, and it would give the correct list of PVs/VG
> membership/size of VGs; so I never thought anything of it (I have a couple
> of disks to play with, once I get the data I take care of db_vol, and I will
> try to replicate my experience).

If you were able to "lvremove /dev/db_vol/snap_db" it shouldn't be 
visible in the metadata I got from you.

But it still is in there and has extents allocated on the physical volume
you wanted to remove from the volumegroup "db_vol". Unless there was no
extents allocated on physical volume /dev/sda, running 
"vgreduce db_vol /dev/sda" was impossible.

The steps needed would have been:

- close /dev/db_vol/db_snap by unmounting it
- successfully removing the LV with "lvremove /dev/db_vol_snap"
- reducing the volume group successfully with "vgreduce db_vol /dev/sda"

To check it:
- vgdisplay -v db_vol # just showing 1 PV in VG "db_vol"
- pvscan              # showing /dev/sda to be an unused PV

> > > 
> > > So, the preferred course here is to "to change the metadata 
> > in order to get
> > > rid of the gone physical volume", and all will be well. 
> > 
> > So there's cons vs. (temporarly) trying 1.1-rc to quorum 
> > activate db_vol
> > in order to retrieve the data?
> > 
> Only to the extent that your message indicated that LVM 1.1-rc2 was unstable
> (BTW, do I only install the userspace tools and retain my LVM 1.0.1rc4
> kernel code (or do I have to patch the XFS cvs kernel with the LVM 1.1-rc2
> kernel code to implement this alternative?)

You can go with just the tools in a temporary location.

> Thanks,
> 	Murthy
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Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***


Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
Mauelshagen at Sistina.com                           +49 2626 141200
                                                       FAX 924446

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