[linux-lvm] vgscan and initrd

[linux-lvm] vgscan and initrd

[lvm]

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Hi, I come seeking sage advice :)

Anyways, I've been busy installing a new Linux system using Gentoo. I am running this on a spare box, Duron 800 w 300mb, with the harddisk connected to the Promise ATA 100 onboard controller as /dev/hde8.

Al goes well, and I create the following partitions

/dev/hde6      swap
/dev/hde7      ext3 fs     /boot
/dev/hde8      lvm

I also create the pv on /dev/hde8 and a logical volume at /dev/lv/ide

/dev/lv/ide is my /

From my running livecd I then chroot'ed into /dev/lv/ide, and then the troubles began. When I run vgscan when chroot'ed it doesn't find any volume groups. When I run vgchange, i claims that the VDGA record doesn't match the kernel, and urges me to run vgscan, running vgscan doesn't solve this problem since it doesn't find the volume groups.

ls -l /dev/lv/ide shows me that my volume group indeed doesn't excist. However, the mount command shows me that /dev/lv/ide is mounted at root. So in summary, I can't find the volumegroup, even tough I am working on/in it.

I decided to go ahead anyways, and created a initrd using lvmcreate_initrd (based on the kernel i made, 2.4.21 ) it does this, and when I boot it loads this initrd as it is supposed to. It neatly finds my /dev/hda and /dev/hdb cdroms, and once insmod'ed it also find /dev/hde, but the it runs vgscan and finds no volumegroups, that causes vgchange to not find anything either. That causes the kernel to panic, since it cannot find root.

Weird thing is, if I boot with any other rescue/livecd, such as SuSE rescue, knoppix or gentoo live cd, I can vgscan and vgchange -ay to find my volume group and logical volume. But once chroot'ed or booting to my new system, I cannot and will not find it.

Does anyone have any suggestions on why vgscan doesn't find anything and how to solve this ?

Many thanx in advance, I have been strugling with this one for almost a week now, and I am out of options. I have been able to install lvm as root on quite a few systems before, including a LFS system, but right now, I am stumped.

best regards
Mark


When I boot from a livecd image, such as 

Re: [linux-lvm] vgscan and initrd

[Mark H. Wood]

Sounds like what I ran into not long ago.  (FAQ material?)  My VG was so
large that vgscan wanted to write out backup info. that was larger than
the free space in the initrd that Red Hat had set up.  It was suggested to
mount a tmpfs volume over /etc, and meanwhile I have been recreating the
initrd image leaving enough space to allow vgscan to run.

vgscan won't actually say it ran out of storage, but that's what was
happening here.

-- 
Mark H. Wood, Lead System Programmer   mwood@IUPUI.Edu
MS Windows *is* user-friendly, but only for certain values of "user".

Re: [linux-lvm] vgscan and initrd

[Mark]

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That's one of the solutions I had heard over at the Gentoo-LVM forums. 

I've tried adjusting my initrd, both to manualy load the pdc_new module (for my raid controller) and adjusting the size of the initial ramdisk to 4096. 

Didn't work. And still I don't get why vgscan wouldn't work while chroot'ed. 

Also, the lvm root partition is only about 6 or 7 gb in size, would that constitute 'to big' ?

What do you mean by

> mount a tmpfs volume over /etc, and meanwhile I have been recreating the
> initrd image leaving enough space to allow vgscan to run.

I can (and did I think) increase the size of the initrd, but how do i mount a tmpfs volume over /etc ??

To be complete, I am running (on the new system anyways) a 2.4.21 kernel, and lvm 1.0.7. 

Booting into the system with any other kernel, such as gentoo-xfs-2.4.19 or Suse-Rescue-2.4.6 works like a charm. 

Still confused, but gratefull for any help

Mark

Re: [linux-lvm] vgscan and initrd

[Mark H. Wood]

Your follow-up makes it sound as though you have a different problem from
mine, but I can answer your question about mounting tmpfs over /etc:

  mount -t tmpfs tmpfs /etc

You wind up with an empty /etc, but at that point there should be no
problem.  vgscan just wants some place to store a metadata backup which
you are going to throw away, and after pivot-root runs you'll have a
different /etc anyway.  If the Gentoo startup scripts are like Red Hat's,
they'll do a second LVM metadata backup into the "real" /etc later.

-- 
Mark H. Wood, Lead System Programmer   mwood@IUPUI.Edu
MS Windows *is* user-friendly, but only for certain values of "user".

Re: [linux-lvm] vgscan and initrd

[Mark de Ruijter]

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I tried to do that just now. 
Sadly, it didn't work. Still vgscan doesn't see any volume group at all. So once again, kernel panic strikes.

This is so frustrating :) I mean, the livecd things boot just fine, but it absolutly refuses to boot to that lvm.

Any more suggestions ?

"Mark H. Wood" <mwood@IUPUI.Edu> wrote ..
> Your follow-up makes it sound as though you have a different problem from
> mine, but I can answer your question about mounting tmpfs over /etc:
> 
>   mount -t tmpfs tmpfs /etc
> 
> You wind up with an empty /etc, but at that point there should be no
> problem.  vgscan just wants some place to store a metadata backup which
> you are going to throw away, and after pivot-root runs you'll have a
> different /etc anyway.  If the Gentoo startup scripts are like Red Hat's,
> they'll do a second LVM metadata backup into the "real" /etc later.
> 
> -- 
> Mark H. Wood, Lead System Programmer   mwood@IUPUI.Edu
> MS Windows *is* user-friendly, but only for certain values of "user".
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] vgscan and initrd

[Herbert Poetzl]

On Fri, Jun 27, 2003 at 11:13:13PM +0200, Mark de Ruijter wrote:
> I tried to do that just now. 
> Sadly, it didn't work. Still vgscan doesn't see any volume group at all. So once again, kernel panic strikes.
> 
> This is so frustrating :) I mean, the livecd things boot just fine, but it absolutly refuses to boot to that lvm.
> 
> Any more suggestions ?

are you sure that the device nodes for the physical
volumes are present? (in case of doubt, try with devfs
and mount at boot option ;)

just an idea ...

best,
Herbert

> "Mark H. Wood" <mwood@IUPUI.Edu> wrote ..
> > Your follow-up makes it sound as though you have a different problem from
> > mine, but I can answer your question about mounting tmpfs over /etc:
> > 
> >   mount -t tmpfs tmpfs /etc
> > 
> > You wind up with an empty /etc, but at that point there should be no
> > problem.  vgscan just wants some place to store a metadata backup which
> > you are going to throw away, and after pivot-root runs you'll have a
> > different /etc anyway.  If the Gentoo startup scripts are like Red Hat's,
> > they'll do a second LVM metadata backup into the "real" /etc later.
> > 
> > -- 
> > Mark H. Wood, Lead System Programmer   mwood@IUPUI.Edu
> > MS Windows *is* user-friendly, but only for certain values of "user".
> > 
> > _______________________________________________
> > linux-lvm mailing list
> > linux-lvm@sistina.com
> > http://lists.sistina.com/mailman/listinfo/linux-lvm
> > read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/