[linux-lvm] 2.03 Volume readable by 2.02?

[linux-lvm] 2.03 Volume readable by 2.02?

[John L. Poole]

I am having problems with a kernel and/or initial ram file system 
booting up in a Xen environment.

The guest virtual machine's root file system is on an lvm volume created 
in Debian.  Dom0 is Debian.
lvm on Debian is: 2.03.02(2).

The guest virtual machine is in Gentoo and I have lvm  2.02.187-r2 
installed therein.  I built my
kernel and initramfs against the 2.02 version of lvm.

My question: should tools of lvm v. 2.02.187 be able to read and access 
a volume created by 2.03.02?

Does the version change between 2.02 and 2.03 mean that the file system 
created by 2.03 tools
may not be readable or accessible by 2.02 tools and libraries?  I'm 
doubting it, but asking.

Gentoo's highest version of lvm is 2.02.187-r2; Gentoo developers have 
lvm 2.03 masked with the note:

      [2.03] Needs LOTS of testing, broke boot on my laptop
      in early attempts, maybe needs matching genkernel work?

source: https://packages.gentoo.org/packages/sys-fs/lvm2

Thank you,

John Poole

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Re: [linux-lvm] 2.03 Volume readable by 2.02?

[John Stoffel]

>>>>> "John" == John L Poole <jlpoole56@gmail.com> 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: https://packages.gentoo.org/packages/sys-fs/lvm2

John> Thank you,

John> John Poole

John> _______________________________________________
John> linux-lvm mailing list
John> linux-lvm@redhat.com
John> https://www.redhat.com/mailman/listinfo/linux-lvm
John> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/


_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] 2.03 Volume readable by 2.02?

[John L. Poole]

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

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

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

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

The question I posed:

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

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

Kind regards,

John Poole


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

On 1/31/2021 3:47 PM, John Stoffel wrote:
>>>>>> "John" == John L Poole <jlpoole56@gmail.com> 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: https://packages.gentoo.org/packages/sys-fs/lvm2
>
> John> Thank you,
>
> John> John Poole
>
> John> _______________________________________________
> John> linux-lvm mailing list
> John> linux-lvm@redhat.com
> John> https://www.redhat.com/mailman/listinfo/linux-lvm
> John> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
-- 
Email Rider

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

_______________________________________________
linux-lvm mailing list
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] 2.03 Volume readable by 2.02?

[John Stoffel]

>>>>> "John" == John L Poole <jlpoole56@gmail.com> 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.

Should.

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
bootup.


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 <jlpoole56@gmail.com> 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: https://packages.gentoo.org/packages/sys-fs/lvm2
>> 
John> Thank you,
>> 
John> John Poole
>> 
John> _______________________________________________
John> linux-lvm mailing list
John> linux-lvm@redhat.com
John> https://www.redhat.com/mailman/listinfo/linux-lvm
John> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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
linux-lvm@redhat.com
https://www.redhat.com/mailman/listinfo/linux-lvm
read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/