[linux-lvm] need help to recover my system

[Heinz J. Mauelshagen]

On Sun, Oct 01, 2000 at 11:42:59AM -0400, Les Hazelton wrote:
> My kernel had LVM support compiled in, not as a module.  I had created an initrd but
> may have not done that correctly.  I think the real problem was that the grub loader
> was installed on the root "/" partition and not the "/boot" partition.  I had booted
> the new configuration several times without problem until I deleted the original "/"
> partition.  That's when I realized where the grub loader was installed.
> 
> When I use linux fdisk I see the entry for hdc5 as Linux LVM (85) and if I do "cat
> /proc/partitions"  there is an entry for /dev/hdc5.
> 
> If, while running my test system with kernel 2.4.0, I run the pvcreate command for
> /dev/hdc5 will that destroy the existing PV, VG, LVM content that is currently their?

Yes. You don't want to do that!

But it only allows you to do that using the "-ff" option of the
pvcreate command. Without that it complains _because_ the physical volume
still belongs to a volume group.

Could you supply the "pvscan -d" and the "vgscan -d" output from your test
system to enable further investigation on why LVM doesn't find your volume
group any longer?

Heinz

> 
> "Heinz J. Mauelshagen" wrote:
> 
> > On Sat, Sep 30, 2000 at 11:02:36PM -0400, Les Hazelton wrote:
> > > I had a Mandrake 7.1 system running the 2.2.17 kernel with LVM and
> > > reiserfs patches applied.  I have a 15Gb partition on /dev/hdc5 which
> > > was one large PV. It supports one VG which has the logical volumes for
> > > /usr, /home, /var, etc... Everything except /boot and / which were on
> > > the hda drive as plain ext2 file systems.
> > >
> > > I decided to move the root partition "/" to a logical volume on hdc5 and
> > > all was going well until I deleted it from the ext2 system on hda6.
> >
> > How did you do that?
> > Did you create an inital ram disk to load the lvm driver and activate
> > the volume group?
> > Otherwise you can't access your volume group(s) anyway from the /boot
> > booted kernel.
> >
> > > So
> > > now I have a perfectly good Linux system contained on the hdc5 PV which
> > > I can't access.
> > >
> > > I have test system (Mandrake 7.2-b) on the hda drive.  It has the
> > > 2.4.0-0.22 kernel distributed my Mandrake and I have been attempting to
> > > recover using that system.  The problem is I keep getting these errors:
> > >
> > > ------------------------------------------------------------------------------
> > > pvscan -- reading all physical volumes (this may take a while...)
> > > pvscan -- ERROR "pv_read_all_pv(): lvm_dir_cache" reading physical
> > > volumes
> >
> > This error means, that no (compatible) entries could be found either
> > in /proc/partitions or, if /proc/partitions doesn't exist, in /dev.
> >
> > Please check that these sources are valid on your Mandrake 7.2-b test system
> > and retry.
> >
> > >
> > > [root at farpt1 /root]# vgscan -v
> > > vgscan -- removing "/etc/lvmtab" and "/etc/lvmtab.d"
> > > vgscan -- reading all physical volumes (this may take a while...)
> > > vgscan -- no volume groups found
> > > -------------------------------------------------------------------------------
> > >
> > > I was going to try a pvcreate for /dev/hdc5  but thought it would wipe
> > > the partition clean and I don't want to start over if there is *any*
> > > hope of recovering it.
> > >
> > > Please, if anyone knows a way to recover this volume,  I would be
> > > extremely grateful for the help.
> > >
> > > Les Hazelton
> >
> > --
> >

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Bartningstr. 12
                                                  64289 Darmstadt
                                                  Germany
Mauelshagen at Sistina.com                           +49 6151 7103 86
                                                       FAX 7103 96
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