How to Perform a Failback Takeover on a System That
Uses Oracle Data Guard Replication
Follow this procedure to restart an application on the original primary cluster, cluster-paris, and to use the current data on the original primary cluster.
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Any updates that occurred on the standby cluster, cluster-newyork, while it was acting as primary are discarded.
The failback procedures apply only to clusters in a partnership. You need to perform the following procedure only once for each partnership.
Note –
Conditionally, you can resume using the data on the original primary cluster-paris. However, you must not have replicated data from the new primary, cluster-newyork, to the original primary cluster, cluster-paris, at any point after the takeover operation on cluster-newyork.
Before You Begin
Before you begin the failback takeover procedure, the clusters must have the following roles:
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The protection group on cluster-newyork is assigned the primary role.
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The protection group on cluster-paris has either the primary role or secondary role, depending on whether the protection group was reached during the takeover.
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If the original primary cluster, cluster-paris, failed, confirm that the cluster is restarted and that the Sun Cluster Geographic Edition infrastructure is enabled on the cluster.
For more information about restarting a cluster, see Booting a Cluster in Sun Cluster Geographic Edition System Administration Guide.
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Recover and revert the new Oracle Data Guard primary database to a standby for the original primary to a point in time before the original primary failed.
Refer to the Oracle documentation, which describes how to perform this step.
Note –You might need to use the dgmgrl command to remove and recreate the Oracle Data Guard Broker configuration.
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Ensure that the original primary cluster, cluster-paris, is again working correctly as the primary as part of the Oracle Data Guard configuration.
oracle (phys-paris-1)$ dgmgrl sys/sysdba_password@sales-svc DGMGRL> show configuration;
If the original primary cluster, cluster-paris, is working correctly, the show configuration command displays the SUCCESS state.
If the original primary cluster was up at the point of failure, it is marked as a deactivated secondary cluster. Also, the original standby cluster is marked as an activated primary.
If the original primary cluster was down at the point of failure, it is marked as a deactivated primary cluster. Also, the original standby cluster is marked as an activated primary.
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Was the original primary cluster, cluster-paris, up or down at the point of failure?
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If the original primary cluster, cluster-paris, was down at the point of failure, update the original standby cluster, cluster-newyork, to a secondary.
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On the original standby cluster, that is, the cluster that has become the new primary cluster, stop the protection group.
phys-newyork-1# geopg stop -e local protectiongroupname
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On the original standby cluster, that is, the cluster that has become the new primary cluster, update the protection group.
phys-newyork-1# geopg update protectiongroupname
The roles are now correct, but both clusters are marked as deactivated.
For more information about synchronizing protection groups, see How to Resynchronize an Oracle Data Guard Protection Group.
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On cluster-paris and on cluster-newyork, locally validate the configuration for each protection group.
Ensure that the protection group is not in an Error state. You cannot start a protection group when the protection group is in an Error state.
phys-paris-1# geopg validate protectiongroupname phys-newyork-1# geopg validate protectiongroupname
For more information, see How to Validate an Oracle Data Guard Protection Group.
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From any node in either cluster, globally activate the protection group on both clusters.
# geopg start -e global protectiongroupname
Once the protection groups are activated on both clusters, you have successfully performed the failback takeover.
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If the original primary cluster, cluster-paris, was up at the point of failure, determine the status of the secondary (that is, the original primary) configuration.
phys-newyork-1# geoadm status
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If the Configuration status is set to OK, synchronize the configurations.
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Initiate a takeover for each protection group on the original primary cluster-paris.
phys-paris-1# geopg takeover [-f] protectiongroupname
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If the configuration for the original standby cluster, cluster-newyork, is marked as Error, validate the configuration for each protection group.
cluster-newyork# geopg validate protectiongroupname
For more information, see How to Validate an Oracle Data Guard Protection Group.
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Globally activate the protection groups on both clusters.
cluster-newyork# geopg start -e global protectiongroupname
Once the protection groups are activated on both clusters, you have successfully performed the failback takeover.
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If the Configuration status is set to Error, resolve the problem.
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Deactivate the secondary (that is, the original primary) configuration that is in the Error state.
phys-newyork-1# geopg stop -e local protectiongroupname
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Force a takeover to make the secondary configuration a primary configuration again and to match the underlying Oracle dgmgrl configuration.
phys-newyork-1# geopg takeover -f protectiongroupname
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On both the cluster-paris and on the cluster-newyork clusters, locally validate the configuration for each protection group.
phys-paris-1# geopg validate protectiongroupname phys-newyork-1# geopg validate protectiongroupname
For more information, see How to Validate an Oracle Data Guard Protection Group.
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From any node in either cluster, globally activate the protection group on both clusters.
# geopg start -e global protectiongroupname
Once the protection groups are activated on both clusters, you have successfully performed the failback takeover.
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