[linux-lvm] vgcreate looks at devices it shouldn't

[linux-lvm] vgcreate looks at devices it shouldn't

[jarausch]

Hi,

on the second machine where I would like to create LVM volumes
I have the following problem

The ZIP drive and the CDROM drive are mapped to
hdd (hdc resp.)  BUT due to a kernel parameter
hdc=ide-scsi hdd=ide-scsi
these are no more accessible as  /dev/hdd /dev/hdc

Now pvcreate /dev/sdb1 works fine but
vgcreate home /dev/sdb1
produces error messages like
ide-scsi: hdd unsupported command in request queue (0)
  ....
and after some such messages
vgcreate -- ERROR "pv_read(): read" reading physical volumes.

AND the desired volume group on my  scsi drive /dev/sdb1
is NOT created.

What can one do about this. How to tell the utilities
to never look at /dev/hd?

I am using lvm-1.0.2

Does this problem vanish with 2.0 ?

Many thanks for a hint,

Helmut Jarausch

Lehrstuhl fuer Numerische Mathematik
Institute of Technology, RWTH Aachen
D 52056 Aachen, Germany

Re: [linux-lvm] vgcreate looks at devices it shouldn't

[Heinz J . Mauelshagen]

On Sat, Feb 23, 2002 at 01:07:35PM +0100, jarausch@igpm.rwth-aachen.de wrote:
> Hi,
> 
> on the second machine where I would like to create LVM volumes
> I have the following problem
> 
> The ZIP drive and the CDROM drive are mapped to
> hdd (hdc resp.)  BUT due to a kernel parameter
> hdc=ide-scsi hdd=ide-scsi
> these are no more accessible as  /dev/hdd /dev/hdc
> 
> Now pvcreate /dev/sdb1 works fine but
> vgcreate home /dev/sdb1
> produces error messages like
> ide-scsi: hdd unsupported command in request queue (0)
>   ....
> and after some such messages
> vgcreate -- ERROR "pv_read(): read" reading physical volumes.
> 
> AND the desired volume group on my  scsi drive /dev/sdb1
> is NOT created.
> 
> What can one do about this. How to tell the utilities
> to never look at /dev/hd?

The supported devices in LVM1 are hard coded :-(

Easy way would be to have a wrapper "myvgcreate" like:

#!/bin/sh
DEVDIR=/dev
SAVDIR=/dev/.SAV
DEVS="hdc hdd"
cmd=$(basename $0)

errcheck () {
   if [ $2 -ne 0 ]; then
      echo -en "$cmd -- $1\n\n" >&2
      exit $2
   fi
}

[ ! -d $SAVDIR ] && mkdir $SAVDIR
cd $SAVDIR >/dev/null 2>&1
errcheck "Can't chdir to $SAVDIR" $?
cd $DEVDIR >/dev/null 2>&1
errcheck "Can't chdir to $DEVDIR" $?
mv $DEVS $SAVDIR
errcheck "Can't move $DEVS form $DEVDIR to $SAVDIR" $?
vgcreate $*
cd $SAVDIR >/dev/null 2>&1
errcheck "Can't chdir to $SAVDIR" $?
mv $DEVS $DEVDIR
errcheck "Can't move $DEVS from $SAVDIR to $DEVDIR" $?
rmdir $SAVDIR >/dev/null 2>&1
errcheck "Can't remove $SAVDIR" $?
exit 0

> 
> I am using lvm-1.0.2
> 
> Does this problem vanish with 2.0 ?

Yes.
LVM 2 Beta 1 provides a configurable device filter which enables
you to exclude device nodes using regular exporessions.

THIS IS BETA SOFTWARE NOT MEANT TO BE USED ON PRODUCTION MACHINES!

Unless you try it on test or otherwise not critical systems,
stay with the above work around.

> 
> Many thanks for a hint,
> 
> Helmut Jarausch
> 
> Lehrstuhl fuer Numerische Mathematik
> Institute of Technology, RWTH Aachen
> D 52056 Aachen, Germany
> 
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@sistina.com
> http://lists.sistina.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://www.sistina.com/lvm/Pages/howto.html

-- 

Regards,
Heinz    -- The LVM Guy --

*** Software bugs are stupid.
    Nevertheless it needs not so stupid people to solve them ***

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Heinz Mauelshagen                                 Sistina Software Inc.
Senior Consultant/Developer                       Am Sonnenhang 11
                                                  56242 Marienrachdorf
                                                  Germany
Mauelshagen@Sistina.com                           +49 2626 141200
                                                       FAX 924446
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