Re: [gentoo-user] Re: LVM2 problem, meta data format change?

[Paul Colquhoun]

On Tuesday, May 28, 2019 5:14:42 P.M. AEST Michael Haubenwallner wrote:
> Hi Paul,
>
> as an LVM user without deeper knowledge, stumbled upon your question without
> any reply yet, and my fear was to run into the same when updating lvm2.
> On 5/17/19 2:26 PM, Paul Colquhoun wrote:
> > Recently I found that new kernels were not booting for me, because they
> > could not assemble the LVM partition that I use for the root filesystem.
> >
> > Booting back to my old kernel still worked.
> >
> > I have tracked this back to the lvm2 version.
> >
> > After booting with the old kernel, I ran lvm and tried the 'fullreport'
> > command.
> >
> > sys-fs/lvm2-2.02.184-r3 gives an error:
> >
> > lvm> fullreport
> >
> >  LV root invalid: visible raid meta LV for raid1 segment
> >  LV root invalid: visible raid meta LV for raid1 segment
> >  Internal error: LV segments corrupted in root.
>
> Searching the web with parts of this error messages leads me to this commit:
> https://github.com/lvmteam/lvm2/commit/dd5716ddf258c4a44819fa90d3356833ccf7
> 67b4
>
> While I have no idea about "visible SubLVs", maybe that commit message can
> tell something to you?
>
> > After backing out to an earlier version, sys-fs/lvm2-2.02.183
> > the 'fullreport' actually gives a report.
> >
> > I'm assuming the only reason the old kernel boots is that it has the older
> > lvm in the initramfs, and once assembled the handover to the live system
> > still works.
> >
> > I can't find anything online that looks like the same thing to me, so I
> > was
> > wondering if anyone here had encountered a similar problem?
> >
> > The next step is to try and find how to update the on-disk lvm meta data
> > so the later versions understand it, hopefully without having to rebuild
> > my system from scratch.
>
> As far as I understand, this doesn't seem like a metadata format _change_,
> but a rare metadata consistency problem that goes unnoticed by the older
> version.


Once I deleted & re-created the logical volume the newer versions had no 
problem.

Unfortunately, since it was my root partition, that took moving data to a 
temporary volume, rebooting from there, re-creating the old LV, moving the 
data back, and rebooting again. Not a quick fix, even if it wasn't that 
difficult.


-- 
Reverend Paul Colquhoun, ULC.     http://andor.dropbear.id.au/
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