Introduction to the configuration and use of Oracle12cDataGuardFarSync (below)

Editor's Notes. In the previous article we shared the creation and configuration of Far Sync Instance in DG, today we come together to learn what happens to log transfers when Far Sync Instance goes wrong and introduce the switchover process in the case of configuring Far Sync Instance.

above Introduction to the Configuration and Use of Oracle12c DataGuard Far Sync (above) The Far Sync Instance configuration is mentioned, and the configuration is configured with max_failure=1 alternate=log_archive_dest_3 parameter in the parameters. When there is a problem with dest_2 it will cut to hit dest_3 for log transfer.

For this parameter refer to

Here's a test to see if dest_3 works when Far Sync Instance has a problem.

Turn off Far Sync Instance

Main Library Switching Log

look over Main Library Log

Backup library dg alert log

The backup library shows normal.

Next we do switchover.

12c dataguard provides a new syntax to implement switchover for dg. test it below.

Main library execution check


switch over

Main Library Log

Far sync transfer log

DataGuard side alert log

View the new main library

---the end

Knowledge supplement: about Far Sync Instance configuration

1. Configuration mode of the simplest Far sync. Configure far sync instances near the master (within the distance limit for achieving synchronization), synchronous transfer between the master and far sync instances, and asynchronous transfer between far sync and the standby, so that even if there is a connection problem between the master and the standby, the data of the master is in the far sync instance, achieving zero data loss.

2. Highly available configuration of Far Sync : Although far sync provides zero-loss data synchronization, everything can go wrong. To avoid data loss due to connection problems between the master and Far Sync, configure two Far Sync instances on the master and automatically switch to the other Far Sync instance when one of the connections goes down.

3. Extended configuration of Far Sync : In an environment where you need to do a master-backup switchover, to ensure that the data transfer is not affected after the switchover, configure Far Sync instances on both nodes. Of course, at the same moment, only one Far Sync instance is active, that is, the Far Sync instance that is close to the current master is active.

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