Bidirectional and Multi-Directional Replication
Bidirectional and Multi-Directional Replication
What is Bidirectional Replication?
Bidirectional or Multi-directional replication is basically 2 or more independent databases that hold data that is consistent amongst each other. In other words they contain the same data such that the same application can run in either one of these servers and expect to retrieve correct consistent data.
It is worthwhile noting that bidirectional replication is different from two phase commits or distributed transactions. Such transactions are not committed until all the databases are updated. This requires that all the databases are active and available or the transaction fails.
In bidirectional replication the transaction for that database completes with that database. This transaction is then captured and forward and delivered into another database and there will always be an inherent lag. If the server(s) for both (or more) databases have constant communication this is considered as real time replication.