Designing Disaster Tolerant High Availability Clusters, 10th Edition, March 2003 (B7660-90013)

Physical Data Replication for ContinentalClusters Using EMC SRDF
Creating and Exporting Volume Groups
Chapter 7 333
Creating and Exporting Volume Groups
Create and export the volume groups using the following procedure:
1. Define the appropriate volume groups on each host system that
might run the application package. Use the commands:
# mkdir /dev/vgxx
# mknod /dev/vgxx/group c 64 0xnn0000
where the name /dev/vgxx and the number nn are unique within the
entire cluster.
2. Create the volume group only on the primary system. Use the
vgcreate and perhaps the vgextend command, specifying the
appropriate special device file names.
3. Export the volume groups on the primary system without removing
the special device files. Use the commands:
# vgchange -a n <vgname>
# vgexport -s -p -m <mapfilename> <vgname>
Note: The vgexport -s option creates the special device files for the
vgimport on adoptive nodes. The vgimport -s option will look for the
marked disks for that volume group. It is expedient, and reduces
error. Unfortunately the alternate pvlink optimization may be
sacrificed. For lots of disks it is a trade off.
Make sure that you copy the mapfiles to all of the host systems.
NOTE See the example scripts add_vgpkgCCA.sh and vgexp_vgpkgCCA.sh
in the Samples-CC directory to see how to automate steps one
through three.
4. Import the VGs on all of the other systems that might run the
MC/ServiceGuard package and backup the LVM configuration. Do
this on both the primary and recovery cluster nodes. Make sure that
you split the logical SRDF links before importing the VGs. A sample
script to split the links is pre.cmquery.
Use the commands: