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

F Metrocluster Command Reference for Preview Utility
This appendix describes the Data Replication Storage Failover Preview utility. This appendix
discusses the following topics:
• Overview of Data Replication Storage Failover Preview
• Command Reference
• Sample Output of the cmdrprev Command
Overview of Data Replication Storage Failover Preview
In an actual failure, packages are failed over to the standby site. As part of the package startup,
the underlying storage is failed over based on the parameters defined in Metrocluster environment
file. The storage failover can fail due to many reasons and can be categorized as the following:
• Incorrect configuration or setup of Metrocluster and data replication environment
The storage failover can fail if the Metrocluster Environment file contains syntax errors, or
invalid parameter values, or the installed Metrocluster binaries are corrupt or have incorrect
file permissions.
Also in the case of Continuous Access EVA, the SMI-S service on the WMS could be down
or the mccaeva.conf file is corrupt or stale. In the case of Continuous Access P9000 or XP,
the possible configuration errors are invalid horcm file, or the command device is not
functional.
• Invalid data replication state
The data may not be in the write-order, which can be due to a track copy at the time of the
failover attempt. Also, the data is not current (lagging behind the primary) and the Metrocluster
environment variables are not set correctly to allow a failover on non-current data.
The command cmdrprev previews the failover of data replication storage. It determines if storage
failover would be successful in an actual package failover scenario. This command can be used
in both Metrocluster and Continentalcluster installations. If the preview fails, the cmdrprev command
displays on stdout a detailed log that identifies the cause for failure.
NOTE: Detailed messages from the preview process are logged into the stdout.
The command exit value indicates if the storage failover in an actual package will succeed or not.
Table 41 describes the exit values of the command.
Table 41 Command Exit Value and its Description
DescriptionValue
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 on any
node in the cluster.
-1
The data replication storage failover preview command failed, due to invalid command usage
or due to invalid input parameters.
The data replication storage failover preview is successful from a specific node.0
This indicates if data replication storage failover will be successful in the event of a package
failover.
The data replication storage failover preview failed.1
This indicates that in the event of an actual recovery process, the data replication storage
failover will not succeed from on any node in the cluster.
The data replication storage failover preview failed due to node specific error conditions or
due to transient conditions.
2
Overview of Data Replication Storage Failover Preview 503