Bug 268581

Description of problem:  
Volume Group fails to come Active


Version-Release number of selected component (if applicable):
device-mapper-multipath-0.4.5-21.0.1.RHEL4

How reproducible:
every time

Steps to Reproduce:
I have a Disaster Recivery system that has 2 identical groups of luns.  When the
D/R server is required for a test (or a real disaster), I need to bring it up
(pointing to one set of luns) for a particular volume group.  I will call them
lun-group A (16 25GB luns) and lun-group B (16 25GB luns).  Keep in mind that
they are absolutely identical, and therefore can not both be active on the
system at the same time. Below is the process I have followed to bring up either
lun-group A or lun-group B:

1) determine which group of luns should come up active on the D/R server.  I
this example I have decided to activate lun-group B (and therefore remove
lun-group A).
2) issue a "dd" command to wipe out the alternate lun-group (lun-group A) e.g.
  dd if=/dev/zero of=/dev/mpath/mpath6 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath7 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath8 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath9 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath10 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath11 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath12 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath13 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath14 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath15 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath16 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath17 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath18 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath19 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath20 bs=1000000000 count=1
  dd if=/dev/zero of=/dev/mpath/mpath21 bs=1000000000 count=1
3) run "pvscan"
4) run "vgscan"
5) run "lvscan"
6) run "vgchange" to activate volume group.  e.g.
  vgchange -ay /dev/nsc01
  THIS IS THE PROBLEM!!  I get the following error:
  volume group nsc01 not found

  
Actual results:
After running the vgchange command (vgchange -ay /dev/nsc01) I got the following
message:

volume group nsc01 not found



Expected results:
the volume group should have come active


Additional info:
I forced the old device-mapper-multipath package on:

rpm -ivh device-mapper-multipath-0.4.5-21.RHEL4 --oldpackage --force

I then removed the latest device-mapper-multipath:

rpm -e device-mapper-multipath-0.4.5-21.0.1.RHEL4

THE Vgchange NOW WORKS!  I believe that
device-mapper-multipath-0.4.5-21.0.1.RHEL4 doesn't allow me to look at my second
group of luns.  In effect, I have lost my second group of critical disk, and the
only way to see it is to remove the latest device mapper update and re-install
device-mapper-multipath-0.4.5-21.RHEL4.