This topic describes the process of failing over a replica. Objects stored in a replica are read-only, and failing over a replica moves the replicated objects to the live system. After a failover, all of the objects will appear in the system as if they had been created locally and will be visible in DCT's unified cross-engine view.

Prerequisites

  • A CD engine that contains a replica is required. Both source and target engines should be registered in DCT.

  • For an overview of what replicas are and what failover implies, see Replicas and failover.

  • For more information on configuring replication, refer to Configure replication.

Procedure

  1. Locate the replica to failover. In DCT, navigate to Data > Policies > Replication and identify the replication policy whose replica you want to fail over.

  2. If the source CD engine is still active, disable any dSource or VDB that is part of the replica being failed over to ensure that only one instance is enabled. In DCT, navigate to Data > Data Management > dSources or Data > Data Management > VDBs to disable the appropriate objects. After disabling the objects, trigger a final replication to get the most recent data to the target. If any scripts are accessing the engine, then you must repoint those scripts to the replication target environment to avoid VDBs from being started up in the old replication source environment.

  3. Initiate failover. To perform a test-failover, read Test-failover and failback first. For a regular failover, proceed with the failover operation.

  4. Wait for completion. The failover will process and the replica objects will be moved to the live system.

  5. Apply configuration changes. Apply any configuration changes that are required to customize the objects for the system. This might include updating object states such as IP addresses, mount paths, or credentials. For more details, see Replicas and failover.

    Before enabling failed-over environments, dSources, and VDBs, add to the target engine's TrustStore the CA certificates from the source engine's TrustStore that are required by the configurations you are enabling, including replication client authentication and CD engine-level certificate-based password vault integrations. See TrustStore settings for the certificate installation procedure.

  6. Enable environments. In DCT, navigate to Home > Infrastructure Connections. The environments that were failed over will be disabled. Enable each one.

  7. Refresh consolidated environments. Refresh any environments that were consolidated during failover.

  8. Enable dSources and VDBs. In DCT, navigate to Data > Data Management > dSources and Data > Data Management > VDBs. Enable each object that was failed over.

If the dSources and VDBs that were failed over belong to a plugin, depending on what version of the plugin existed on the target engine, the plugin may be in an inactive state. The plugin must be moved out of the inactive state before the object can be enabled.

After replication failover

Delete the replication policy that is no longer needed after failover.

To preserve user access, confirm that the DCT scoped role includes the failed-over VDB or matches one of its tags. A role that includes only the source VDB does not automatically include its replica. For details, see Configure replication.

A failover is similar to a migration operation for TDE-enabled vPDBs. If after the failover the original target hosts are still available, then the vPDB can be enabled on the failed-over CD engine without requiring additional manual steps. If the vPDB is to be restored to a different target host, then the same manual steps are required for migration, as the vPDB will now be located on a new target and thus needs the artifact directory, parent Keystore, and merged Keystore available.

Last updated
Oct 8, 2026