STEPS NECESSARY TO USE A VG IN A HANFS CONFIGURATION
ITEM: RTA000025785
QUESTION:
Customer currently has a system with a volume group on external disks.
We are trying to 'convert' this system to a HANFS system. The docs
only explain how to create a shared VG from scratch. Since our VG
is already created (and we don't' want to delete and recreate it)
we tried to determine the major number on the VG by using the
lsvgchkmajor command with major numbers until we got a return without
error.
The command says that it should echo the major # that you entered if
it matches the VG's major number or it should output the smallest avail-
able major number. We can get it to echo what we THINK is the major
number for the VG but when we use any other number the command just
returns an error message.
Are we correct in assuming that if we enter lvchkmajor 22 datavg
and the command returns 22 then we have found the major number that
the VG was created with? Is there a better way to find the major number
for a VG after it has been created?
To throw a wrench in this situation the second system of the HANFS pair
is a more powerful model than the one that the VG is defined on. I know
that all shared VG work must be done on only one system. We want to
move ownership of the VG to the new, faster system. We have tried
to do this by varying off and exporting the VG from the current system
and then tried to import the VG with the major # of 22 (from the lsvgck-
major command) onto the new, faster system so that all maintenance can
be done on it. Will this work?
Please describe the steps necessary to use a VG that is already created
in a HANFS configuration. Also, please include instructions on how
to move ownership of an already created VG from one system to another
so that it can be used in an HANFS environment.
One last question - does the /etc/exports.hanfs file need to be created
on both the primary and backup systems?
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A:
1) The following are the steps to follow to move a vg from one
system to another for use with HANFS:
Make sure the vg is on a external chain of drives.
Export the volume group from the original machine.
Remove the external drives and delete the devices associated
with the volume group.
Configure both machines for HANFS using the normal steps for
hardware configuration. Use the external disks that contain
the needed volume group.
Instead of creating a SVG on the server machine simply import
the volume group that already exists on the external drives,
set the major number the same on both systems.
After the vg has been imported on the server, continue with
the HANFS configuration normally after the step to create the
SVG.
2) The /etc/exports.hanfs file does need to exist on both
both the server and backup machines. After creating this file
on the server, copy the file onto the backup machine.
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QUESTION:
Please clarify further on the import of the SVG. Does a VG carry
the major number with it after it is exported from a system?
All of the HANFS docs say that the SVG must have the same major
number between systems. When I import the VG to my new server
do I have to specify the major number of the VG when it existed
on the previous owner? If I specify a different VG major number
when I import it on the new owner I assume that I'll use that
same number when I import it back to the previous owner as a SVG??
If I do need to supply the original major number please provide a
method of determining what the major # is for the VG so that I can
provide that # when doing the import.
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A: The major number is not actually associated with the VG it is
associated with the device driver for the VG. So when you export
a VG the major number is not saved in the VGDA. When you import
a VG, you create a new device and can specify the major number for
the driver.
What you need to do is use the command "lvlstmajor" on both machines
before importing the VG on either one. This command lists all the
available major numbers. Choose a number that is available on both
machines, then import the volume group on the server using that
major number. After the server is setup, use the same major number
when importing the volume group on the backup machine.
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QUESTION:
What are the ramifications of using a major number that was not
listed as being available when the lvlstmajor command was issued?
We imported the VG with a major number of 22, thinking that we had
to use that number since that is what it seemed to be on the other
system (we did this before we got your last answer). Now, knowing
that the major # is not carried in the VGDA, we plan on exporting
the VG and importing it back with a number that is available on
both systems.
Will this work OK? FYI, we did get a warning msg about having
a duplicate LV when we did the import. I'm guessing now that the
LV had the major number of 22.
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A: You should be safe as long as you follow the steps listed in the
previous response. Export the VG, delete any related devices,
and reimport the VG with the new major number that is available
on both machines.
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This item was created from library item Q601379 BQZVG
Additional search words:
AIX ALTERNATE BQZVG CREATED GROUP HANFS INDEX IX OCT92 OP OZNEW
RISCOSO RISCSYSTEM SOFTWARE SYS VOL VOLUME
WWQA: ITEM: RTA000025785 ITEM: RTA000025785
Dated: 11/1996 Category: RISCOSO
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