2 node MCSG OPS cluster

[Robert Shong]

I need to create a mirror using lvextend (-m) but would like to do most of it while system is online (with minimal downtime anyway). Is it possible to bring up a 2-node OPS cluster in a single cluster mode, with originally "shared" VGs in "exclusive" mode so that LVM based mirroring can take place while users are still online? If so, what are the steps involved? Needless to say, once the mirrors are in synch, we will change VGs back to "shared" mode and bring up cluster.

Thanks in advance for your help.

[Geoff Wild]

The volume groups must be cluster aware - not exclusive to be in a running cluster.

However, you can mirror the disks while the cluster is up.

For step, see "Creating a Storage Infrastructure with LVM" section in "Managing MC/ServiceGuard":

http://docs.hp.com/hpux/onlinedocs/B3936-90073/B3936-90073.html

Rgds...Geoff

[Saurav_1]

Hi,

Pls explain the setup clearly.

Saurav

[Stephen Doud]

I don't know the answer to this fundamental question - will OPS work with a VG that is not activated in SHARED mode, even when only one server is running an instance on that VG?
If the answer is YES proceed. If not, skip the part below where the package control script is editted and don't start the package

As you may know - VG's configured to activate in "shared" mode cannot be altered with LVM commands (see most any LVM command name page). So to add a mirror, the VG must be configured to activate in either "exclusive" mode or normal mode.

# cmhaltpkg
# vgchange -c n -S n

On the node where you want to start the package, edit the package control script and change the VGCHANGE parameter to: 'vgchange -a y'.
Start the package:
# cmrunpkg

If OPS cannot work with a VG that is not marked as a "shared" VG, then don't start the package and do the following step:
# vgchange -a y

In either case, with the VG activated, add the mirrors:
# lvextend -m 1
Repeat as needed on each lvol.

When mirroring is completed:

- if the package is up - halt it
# cmhaltpkg
Edit the package control script - reverting the VGCHANGE parameter:
'vgchange -a s'

- With the package down:
# vgchange -a n
# vgchange -c y -S y

Start the OPS packages

-sd