Designing Disaster Recovery Clusters using Metroclusters and Continentalclusters, Reprinted October 2011 (5900-1881)

3. Distribute the package configuration changes, if any.
# cmapplyconf -P pkgname.config
4. Start the package with the appropriate Serviceguard command.
# cmmodpkg -e pkgname
Planned node maintenance is treated the same as a failure by the cluster. If you take a node
down for maintenance, package failover and quorum calculation is based on the remaining
nodes. Make sure that nodes are taken down evenly at each site, and that enough nodes
remain on-line to form a quorum if a failure occurs. See “Example Failover Scenarios with
Two Arbitrators” (page 30).
Remote Copy Link Failure and Resume Modes
When the link is failed, snapshots are created for all primary volumes, but no snapshots are created
for secondary volumes while replication is stopped. When replication is restarted for the volume,
all differences between the base volume and the snapshot taken when the replication was stopped
are sent over in order to resynchronize the secondary volume with the primary volume.
Upon Remote Copy links recovery, HP 3PAR Remote Copy automatically restarts the replication if
the auto_recover policy is set. If the auto_recover policy is not set, when the links are
restored, you can copy any writes from the primary to the secondary groups by issuing the
startrcopygroup command on the system that holds the primary group to resynchronize the
primary and secondary groups.
Restoring replication after a failover
When the Metrocluster package fails over to the remote site and the links are not up or the primary
storage system is not up, Metrocluster issues the setrcopygroup failover command. This
command changes the role of the Remote Copy volume group on the storage system in the recovery
site from “Secondary” to “Primary-Rev”. In this role, the data is not replicated from the recovery
site to the primary site. After the links are restored or the primary storage system is restored,
manually issue the setrcopygroup recover command on the storage system in the recovery
site to resynchronize the data from the recovery site to the primary site. This will result in the change
of the role of the Remote Copy volume group on the storage system in the primary site from "Primary"
to "Secondary-Rev".
CAUTION: When the roles are "Secondary-Rev" and "Primary-Rev", a disaster on the recovery
site will result in a failure of the Metrocluster package. To avoid this, immediately halt the package
on the recovery site and start it up on the primary site. This will restore the role of the Remote Copy
volume group to its original role of "Primary" and "Secondary".
Completing and Running a Continentalclusters Solution with 3PAR Remote
Copy
The following section describes how to configure Continentalclusters solution using HP 3PAR Remote
Copy, which requires the Metrocluster with 3PAR Remote Copy product.
Solution Overview for Continentalclusters using 3PAR Remote Copy
The Continentalclusters mutual recovery configuration with 3PAR Remote Copy is shown in Figure 56.
326 Building Disaster Recovery Serviceguard Solutions Using Metrocluster with 3PAR Remote Copy