Preparing for a failover of the CDC Replication Engine for Oracle databases

To prepare for a failover such as a hardware or software failure, your clustering environment will require a script that performs CDC Replication tasks on the new active node.

About this task

The tasks in the following steps must be included in your failover script.

Procedure

  1. Clean the transaction queues for each instance by removing all files that begin with txqueue* in the <CDC replication installation directory>/instance/<instance name>/txnstore directory.
  2. Back up your metadata for each instance by archiving all files that begin with md* in the <CDC replication installation directory>/instance/<instance name>/conf directory. If the metadata database does not recover after a failover, restore these files to the same directory on the new active node. This task is optional.
  3. Back up your Event Log messages for each instance by archiving all files in the <CDC replication installation directory>/instance/<instance name>/events directory. If the events database does not recover after a failover, restore these files to the same directory on the new active node. This task is optional.
  4. Start each instance on the new active node with the following command: dmts64 - I <instance_name>
  5. Run the dmclearstagingstore command on the new active node for all instances.
  6. Start all subscriptions on the new active node with the dmstartmirror command.