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

[Michael Haubenwallner]

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/dd5716ddf258c4a44819fa90d3356833ccf767b4

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.

HTH,
/haubi/