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

Table 32 Command Exit Value and its Description
DescriptionValue
The data replication storage failover preview command failed, due to invalid command usage or
due to invalid input parameters.
—1
The data replication storage failover preview is successful from a specific node. This indicates if
data replication storage failover will be successful in the event of the package failing over to this
node.
0
The data replication storage failover preview failed. This indicates that in the event of an actual
recovery process, the data replication storage failover will not succeed from any node in the cluster.
1
The data replication storage failover preview failed due to node specific error conditions or due to
transient conditions. This indicates that in the event of an actual recovery process, the data replication
2
storage failover will not succeed on that node. Failover may be successful if attempted at a later
time or attempted on a different node in the cluster.
When run on a Metrocluster node at the site connected to the target storage of the DC1-DC2
replication pair, the cmdrprev command previews data replication preparation for a Metrocluster
remote failover.
When run on a Metrocluster node connected to the source storage of the DC1-DC2 replication
pair, the command previews the data replication preparation for a local failover. When run on a
node in the recovery cluster, the cmdrprev command previews data replication preparation for
a Continentalclusters recovery. Since the command does not change the data replication
environment, it can be run even if the package associated with the data replication storage is up
in the 3DC solution. If the FORCEFLAG file is present in the package directory, the actual data
replication storage failover will remove it. Inline with the actual behavior, the cmdrprev command
also removes the FORCEFLAG file present in the package directory. For more information on using
cmdrprev, see Appendix “F Metrocluster Command Reference for Preview Utility”.
NOTE: The cmdrprev command does not check the configuration of the Remote Command
Devices and Device Group Monitor.
Testing the application startup at the recovery cluster
To verify that the application can be started successfully at the recovery cluster, complete the
following procedure during the planned downtime for maintenance:
1. Halt the primary package running in the primary cluster (Metrocluster) using the cmhaltpkg
command. When complex workloads are used, the Site Controller package is halted which
brings down the corresponding complex workload stack running in DC1.
2. This step is required only if you are using 3DC CAJ/CAJ Tri-Link configuration. Else, go to
step 3.
Delete the Delta Resync pair from DC3 node:
# pairsplit –g <Delta Resync-pair> -R
3. Split the Active-CAJ pair to make it read-write at the recovery cluster. For suspending replication,
split the Continuous Access journal device group pair, over which the replication is happening
to DC3 currently, using pairsplit –RS command from a node in DC3:
# pairsplit –g <Active-CAJ-pair> -RS
4. Change the Cluster ID of all LVM and SLVM volume groups managed by the application. For
LVM volume groups, run the following commands from a node in the primary cluster to change
the cluster ID:
# vgchange -c n <vg_name>
# vgchange -c y <vg_name>
For SLVM volume groups, run the following commands from a node in the primary cluster to
change the cluster ID:
462 Designing a Three Data Center Disaster Recovery Solution