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From: "John Stoffel" <>
Cc: LVM general discussion and development <>
Subject: Re: [linux-lvm] 2.03 Volume readable by 2.02?
Date: Tue, 2 Feb 2021 13:02:32 -0500	[thread overview]
Message-ID: <24601.37816.31387.379244@quad.stoffel.home> (raw)
In-Reply-To: <>

>>>>> "John" == John L Poole <> writes:

John> Thank you, John Stoffel, for your kind offer to help.  I am
John> faced with several alternatives at this juncture and feel that
John> enlisting general help would be counter-productive.  I don't
John> want you to spend your time on an approach only to have me
John> change the whole paradigm, i.e. installing Gentoo as Dom0 (and
John> wrestling wieh EUFI) so there is no disparity between lvm
John> versions.  I've invested several hours building out my guest
John> Gentoo, so I hate to risk having to do it over again, or trying
John> to archive and copy it to an attached drive and then back into a
John> partition using fdisk or parted.

Have you checked that your initramfs image built with your Gentoo VM
has the correct LVM drivers installed?

But since you haven't posted any error messages or logs, no one is
going to be able to help you.  

John> I asked the question below hoping a developer familiar with the
John> specifications of the mapping schema for lvm might answer.  Are
John> you one of the developers at Redhat?

Nope, I don't work at RedHat.

John> Since I posted, I changed my client's lvm to 2.0.3.  This
John> upgrade and near match to the host ("Dom0") version ought to
John> negate any disparity issues between versions -- I would hope.


John> Even with my Gentoo client having 2.0.3 trying to discover the
John> lvm shares created by the Debian host is failing at the start of
John> the kernel.  I think my problem is the initramfs is not properly
John> mapping to the lvm system.  This may be a Xen issue or something
John> missing in my guest kernel and/or initramfs.

Correct, I suspect your initramfs of your client doesn't have the
properl LVM modules installed.  Did you compile your kernel with LVM
support as well?  

John> The question I posed:

John>     should tools of lvm v. 2.02.187 be able to read and access
John>     a volume created by 2.03.02?

Yes, it should be able to do so.  You could test this by booting an
older Debian netboot image in your environment and making sure that it
can see the volumes.  

John> raises the question of whether a previous version at 2.02 can
John> read a mapped system created by a version at 2.03.  An answer
John> could be helpful for others working with Virtual Machines so I
John> hope someone who might know the answers responds.

Again, you need to post logs, or even the screenshot of the console as
your client VM boots up so we can see what's really happening.
Details matter, and trying to look for help from a core developer
isn't going to help since they will just ask what I'm asking here.

Post logs.  Post the output of your console on client bootup.  Ideally
bootup your client with a serial console.  Try booting the basic
gentoo image they provide and see if that works.  Make sure you have
the LVM kernel interfaces either compiled into your kernel, or that
the modules are present in the initramfs so they can be found on

John> I could not find a description of posting etiquette for this forum.

You're doing fine!  Don't sweat it.  

John> On 1/31/2021 3:47 PM, John Stoffel wrote:
>>>>>>> "John" == John L Poole <> writes:
John> I am having problems with a kernel and/or initial ram file
John> system booting up in a Xen environment.
>> Do you have any logs of the error(s) when booting up?
>> Can you show us the configuration of your Xen guest and it's LVM
>> volumes, VG and PVs as well?  The more details the better.
>> I personally don't do Gentoo or Xen, so I can't help there.  But I can
>> ask you to post more details.  A boot log would be very helpful.
John> The guest virtual machine's root file system is on an lvm volume created
John> in Debian.  Dom0 is Debian.
John> lvm on Debian is: 2.03.02(2).
John> The guest virtual machine is in Gentoo and I have lvm  2.02.187-r2
John> installed therein.  I built my
John> kernel and initramfs against the 2.02 version of lvm.
John> My question: should tools of lvm v. 2.02.187 be able to read and access
John> a volume created by 2.03.02?
John> Does the version change between 2.02 and 2.03 mean that the file system
John> created by 2.03 tools
John> may not be readable or accessible by 2.02 tools and libraries?  I'm
John> doubting it, but asking.
John> Gentoo's highest version of lvm is 2.02.187-r2; Gentoo developers have
John> lvm 2.03 masked with the note:
John>      [2.03] Needs LOTS of testing, broke boot on my laptop
John>      in early attempts, maybe needs matching genkernel work?
John> source:
John> Thank you,
John> John Poole
John> _______________________________________________
John> linux-lvm mailing list
John> read the LVM HOW-TO at
John> -- 
John> Email Rider

John> John Laurence Poole
John> 1566 Court ST NE
John> Salem OR 97301-4241
John> 707-812-1323 office

linux-lvm mailing list
read the LVM HOW-TO at

      reply	other threads:[~2021-02-02 18:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-30 16:14 [linux-lvm] 2.03 Volume readable by 2.02? John L. Poole
2021-01-31 23:47 ` John Stoffel
2021-02-02  4:13   ` John L. Poole
2021-02-02 18:02     ` John Stoffel [this message]

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