[linux-lvm] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[linux-lvm] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Daniel J Hannum]

Hi. I feel dumb for subscribing to the list just so I can yell out my
problem and hopefully someone can help, but I'm at the end of my rope
here.

Here's the situation. I just installed Debian 3.0 testing and I set it up
so that I was using their lvm10 package (version 1.0.4-6) for /usr, /var
/home, etc. (NOT /) It works fine off the kernel that Debian uses in its
install (2.4.18-bf2.4). BUT, if I install a stock Debian kernel with
apt-get (kernel-image-2.4.18-k7), lvm cannot see my physical volumes at
boot-time.

vgscan works fine, it detects my volume group 'main'

but vgchange does this:

vgchange -- ERROR: can't get name(s) of physical volumes
vgchange -- please check, if /proc is mounted

Now, since it works with one kernel but not with the other, well, it must
that there's something wrong with the stock Debian kernel. Except that
this same kernel booted this volume group multiple times before. So the
problem is something aside from the kernel itself.

There is a message that Debian's lvm10 package gives you when you install
it. Apparently, IF you have devfs in the kernel (and the broken kernel
does) then devfs must be mounted (which I think it is... /dev/.devfs
exists) OR devfsd must be installed (which I also did, to be safe). If you
don't do this, the stock kernels won't read the lvm physical volumes.
Sounds familiar, no? But I think I did what the package script told me to
do, and it still can't find them.

Now, I'm no newbie, and so if I only knew what that error message meant,
maybe I could fix it. The /dev/main/* devices exist, but I can't mount
them. /proc/lvm exists, but /proc/lvm/VGs doesn't contain my VG's. What
would cause lvm to see my volume group and set up the devices right
(according to the names of the lv's), but not be able to find the physical
volumes.

I know this came up before on the list (like 18 months ago), but the
thread wasn't helpful.

I would be grateful for any assistance. I can post diagnostic info, if you
tell me what to type :)

thanks

dan

Re: [linux-lvm] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Steven Lembark]

> Here's the situation. I just installed Debian 3.0 testing and I set it up
> so that I was using their lvm10 package (version 1.0.4-6) for /usr, /var
> /home, etc. (NOT /) It works fine off the kernel that Debian uses in its
> install (2.4.18-bf2.4). BUT, if I install a stock Debian kernel with
> apt-get (kernel-image-2.4.18-k7), lvm cannot see my physical volumes at
> boot-time.

Make sure that the stock kernel has LVM	installed, then
upgrade to 1.0.6 (via http://www.sistina.com/). Building
a 2.4.10 kernel w/ 1.0.6 (if you want to stick with 1.0)
should give you the best results.


--
Steven Lembark                               2930 W. Palmer
Workhorse Computing                       Chicago, IL 60647
                                            +1 800 762 1582

Re: [linux-lvm] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Daniel J Hannum]

On Sat, 14 Dec 2002, Steven Lembark wrote:

>
> > Here's the situation. I just installed Debian 3.0 testing and I set it up
> > so that I was using their lvm10 package (version 1.0.4-6) for /usr, /var
> > /home, etc. (NOT /) It works fine off the kernel that Debian uses in its
> > install (2.4.18-bf2.4). BUT, if I install a stock Debian kernel with
> > apt-get (kernel-image-2.4.18-k7), lvm cannot see my physical volumes at
> > boot-time.
>
> Make sure that the stock kernel has LVM	installed, then
> upgrade to 1.0.6 (via http://www.sistina.com/). Building
> a 2.4.10 kernel w/ 1.0.6 (if you want to stick with 1.0)
> should give you the best results.
>

No difference. The kernel (both the working and non-working kernels) have
lvm as a module. /proc/modules lists lvm-mod in both cases. I upgraded to
1.0.6 (Debian unstable) and the same thing happens.

What causes the "can't find name(s) of physical volumes" error? Anybody
know?

>
> --
> Steven Lembark                               2930 W. Palmer
> Workhorse Computing                       Chicago, IL 60647
>                                             +1 800 762 1582
>
> _______________________________________________
> 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] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Patrick Caulfield]

On Sat, Dec 14, 2002 at 08:53:21PM -0500, Daniel J Hannum wrote:
> Hi. I feel dumb for subscribing to the list just so I can yell out my
> problem and hopefully someone can help, but I'm at the end of my rope
> here.
> 
> Here's the situation. I just installed Debian 3.0 testing and I set it up
> so that I was using their lvm10 package (version 1.0.4-6) for /usr, /var
> /home, etc. (NOT /) It works fine off the kernel that Debian uses in its
> install (2.4.18-bf2.4). BUT, if I install a stock Debian kernel with
> apt-get (kernel-image-2.4.18-k7), lvm cannot see my physical volumes at
> boot-time.

The stock debian kernel has devfs compiled into it. :( 
So if you look in /proc/partitions it will show devfs device names
rather than the "traditional" ones, although the devfs names are not
actually avaiable to you. This confuses LVM.

What you will need to do is to mount devfs at boot time (devfs=mount on
the kernel command-line) on /dev and run devfsd (apt-get install devfsd) and 
things should work.

-- 

patrick

Re: [linux-lvm] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Daniel J Hannum]

Thanks a ton. Debian needs to make their documentation more clear. When
you install lvm, they say to either mount devfs (they don't say how) OR
install devfsd. Turns out, that should be AND. I had to send the kernel
param like you said. And it doesn't work without devfsd, either.

I'm not sure about this weird devfs thing... I guess it's the big new
thing so I better get used to it :)

Anyway, thanks.

dan

On Sun, 15 Dec 2002, Patrick Caulfield wrote:

> On Sat, Dec 14, 2002 at 08:53:21PM -0500, Daniel J Hannum wrote:
> > Hi. I feel dumb for subscribing to the list just so I can yell out my
> > problem and hopefully someone can help, but I'm at the end of my rope
> > here.
> >
> > Here's the situation. I just installed Debian 3.0 testing and I set it up
> > so that I was using their lvm10 package (version 1.0.4-6) for /usr, /var
> > /home, etc. (NOT /) It works fine off the kernel that Debian uses in its
> > install (2.4.18-bf2.4). BUT, if I install a stock Debian kernel with
> > apt-get (kernel-image-2.4.18-k7), lvm cannot see my physical volumes at
> > boot-time.
>
> The stock debian kernel has devfs compiled into it. :(
> So if you look in /proc/partitions it will show devfs device names
> rather than the "traditional" ones, although the devfs names are not
> actually avaiable to you. This confuses LVM.
>
> What you will need to do is to mount devfs at boot time (devfs=mount on
> the kernel command-line) on /dev and run devfsd (apt-get install devfsd) and
> things should work.
>
> --
>
> patrick
>
>
> _______________________________________________
> 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] help: can't read name(s) of physical volumes (Debian kernel weirdness also involved)

[Patrick Caulfield]

On Sun, Dec 15, 2002 at 06:25:47PM -0500, Daniel J Hannum wrote:
> Thanks a ton. Debian needs to make their documentation more clear. When
> you install lvm, they say to either mount devfs (they don't say how) OR
> install devfsd. Turns out, that should be AND. I had to send the kernel
> param like you said. And it doesn't work without devfsd, either.

Actually it is possible to get it to work without devfsd but it's just too
annoying IMHO :)
 

patrick