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

Reconfiguring Recovery Group Site Identities in Continentalclusters after a Recovery
In a disaster scenario where the primary site goes out of operation, but there was no loss of data
on the storage systems or the servers. The recovered application can continue to run at the recovery
site without requiring to fail back on the primary site. It is desirable to have the same level of
recovery capabilities for the applications in their new site, as they had in their original primary
site. To achieve this, Continentalclusters can be reconfigured to provide monitoring and recovery
for the application now running on its recovery site. This is done by switching the identities of the
sites in the applications context. (that is, the old (or original) primary site will become the recovery
site and the old (or original) recovery site will become the primary site. This type of reconfiguration
for Continentalclusters is possible only in a two cluster and two site configurations.
Continentalclusters solutions using HP 3PAR storage systems will need no disk array replication
related tasks during the reconfigurations. Once the primary site HP 3PAR storage system comes
back online, resynchronize the data making the recovery site as “source” and the old primary site
as “destination”.
Use the cmswitchconcl command (only in a two cluster configuration) to swap the site identities
for all or a selected application’s recovery group. This is so that the applications can now be
monitored and recovered from their once source disk site.
Troubleshooting
To troubleshoot problems with Metrocluster with 3PAR Remote Copy, you must understand HP
3PAR Remote Copy environments. See the Remote Copy User Guide for more information on
Remote Copy configuration and volume group states.
CAUTION: Metrocluster with 3PAR Remote Copy cannot handle Remote Copy volume group
states automatically and correctly, if they result from manual manipulations (either through HP 3PAR
Management Console or CLI or through any other means).
Metrocluster Log
Make sure you periodically review the following files for messages, warnings, and recommended
actions. It is recommended to review these files after each system, data center, and/or application
failures:
• View the system log at /var/adm/syslog/syslog.log.
• The package log file specified in the package configuration using the parameter
“script_log_file”.
HP 3PAR storage system log
A task, identified by task IDs is generated for each operation in the HP 3PAR storage system. Task
manager commands provide information regarding the tasks in the system. For more information,
see Managing Tasks section in 3PAR CLI Administrator’s Manual available at: http://www.hp.com/
go/saw or contact your HP representative.
NOTE: Match the 3PAR storage system time with the cluster node time so that tasks can be easily
mapped to Metrocluster operations.
For log messages from the 3PAR storage system, you can use showevent and showalert
commands. For more details, see Mangaing Events and Alerts section in HP 3PAR CLI's Administrator
Manual available at: http://www.hp.com/go/saw or contact your HP representative.
Understanding Metrocluster Package Log Messages
Table 26 describes the various messages that are logged in the log files, and the methods to resolve
those error messages.
Troubleshooting 331