[linux-lvm] vgchange -a y /dev/System fails

[Heinz J . Mauelshagen]

On Tue, Jan 29, 2002 at 01:57:38PM -0800, Marc MERLIN wrote:
> [Adding a Cc to lvm-devel, since I apparently hit a bug in the code. Please
> remove or edit as appropriate]
> 
> On Mon, Jan 28, 2002 at 10:42:58AM +0100, Heinz J . Mauelshagen wrote:
> > > It fails and says:
> > > parameter error setting up snapshot copy on write exception
> > > 
> > > So yes, I have  snapshots in there, but I can't delete  the snapshots if the
> > > volume isn't active, and I can't activate the volume because of a snapshot.
> > > 
> > > To make things worse, /dev/System contains /usr and /var.
> > > 
> > > The snapshots were created with 1.0.1rc4 on 2.4.14 and I now run 2.4.17 with
> > > 1.0.1rc4-ish
> > 
> > I am afraid you need to figure out the last metadata backup in /etc/lvmconf/
> > which *doesn't* contain the flaky snapshot(s).
> > 
> > You didn't mention the name of you VG so let's say it was 'A'.
> >
> > You can do that with "vgcfgrestore -f /etc/lvmconf/A.conf.1.old -n A -ll".
> > Replace the '1' in the metadata backup filename above with 2, 3 and so on
> > (you should have a default of up to 9).
> > After you found one (say #3), remember all you PVs belonging to that VG and run
> > 
> > pvcreate -yff /dev/AllYourPVsBelongingToA
> > for pv in /dev/AllYourPVsBelongingToA
> > do
> >    vgcfgrestore -f /etc/lvmconf/A.conf.3.old -n A $pv
> > done
> > vgscan
> > vgchange -ay A
> 
> Unfortunately, that doesn't work because I  had a cron job that was creating
> daily snapshots (in an attempt to emulate ONTAP's snapshot's feature), so my
> 10 backups contain snapshot LVs

Well, in this case you might still have a consistent backup with snapshots
which you can use like mentioned above.

> 
> If the backups were text, I could edit them and remove the snapshot info in
> there, but with a binary backup, I don't know how to do that.
> 
> If I  know how big  my /var and  /usr partitions were  and in which  order I
> created them (vgcfgrestore -ll shows this  anyway), can I recreate the VG on
> top of itself without losing the data in the the LVs?
> Is there another way to recover from this?
> 
> More importantly, is this a known bug? Can I give info to help fix it?

We get ocassional problem reports like yours.
Any syslog or console output which is related to a snapshot flaw would help.

> 
> Marc
> -- 
> Microsoft is to operating systems & security ....
>                                       .... what McDonalds is to gourmet cooking
>   
> Home page: http://marc.merlins.org/   |   Finger marc_f at merlins.org for PGP key
> 
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-- 

Regards,
Heinz    -- The LVM Guy --

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

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