Building Disaster Recovery Serviceguard Solutions Using Continentalclusters A.08.00

Under normal circumstances, Continentalclusters does not allow a package to start in the recovery
cluster unless it can determine that the package is not running in the primary cluster. In some cases,
communication between the two clusters might be lost, and it might be necessary to start the
package on the recovery cluster anyway. To do this, use the cmforeconcl command, which is
used along with a cmrunkpg or cmmodpkg command, as in the following example:
# cmforceconcl cmrunpkg -n node3 Pkg1
CAUTION: When using the cmforceconcl command, ensure that the other cluster is not running
the package. Failure to do this might result in the package running in both clusters, which causes
data corruption.
Adding or Removing a Node from a Cluster
To add a node or to remove a node from Continentalclusters, use the following procedure:
1. Halt any monitor packages that are running.
# cmhaltpkg ccmonpkg
2. Add or remove the node in a cluster by editing the Serviceguard cluster configuration file and
applying the configuration.
# cmapplyconf -C cluster.config
3. Edit the Continentalclusters configuration ASCII file to add or remove the node in the cluster.
4. If a new node is added, then setup SSH equivalence as described in the “Sample
Continentalclusters Configuration” (page 9).
If a node is removed, delete Continentalclusters user along with its HOME directory to remove
all SSH credentials.
5. Verify and apply the configuration using the cmcheckconcl and cmapplyconcl commands.
6. Restart the monitor packages.
7. View the status of Continentalclusters.
# cmviewconcl
Adding a Recovery Group to Continentalclusters
To add a new package to the Continentalclusters configuration, it is necessary to configure a new
primary package and recovery package. Then, you must add a new recovery group to the
Continentalclusters configuration file. In addition, it is necessary to ensure that the data replication
is provided for the new package, using either software based replication or array based replication.
Adding a new package does not require bringing down either cluster. However, to implement the
new configuration:
1. Configure data replication for the applications to be configured as packages.
2. Configure the new primary and recovery packages by creating and editing package
configuration files.
3. Use cmapplyconf command to add the primary package to one cluster, and the recovery
package to the other cluster.
4. Create a new recovery group in the Continentalclusters configuration ASCII file.
5. Halt the monitor packages on both clusters.
6. Use the cmapplyconcl command to apply the edited Continentalclusters configuration file.
7. Restart the monitor packages on both the clusters.
8. View the status of the Continentalclusters.
# cmviewconcl
Adding or Removing a Node from a Cluster 59