AWS DMS Explained – Replication Instance and Tasks Amazon Web Service Database Migration Service is used to migrate a database from a source to a target database. It can be between two points with the same source and target engines like Oracle to Oracle or between different databases like Oracle to PostgreSQL database. However, AWS database migration service, at least one end-point must be in the cloud. AWS DMS does not migrate on-premises databases to other on-premises ones. Replication Instance One of the critical components of the AWS database migration service is the replication instance. It is a managed Amazon Elastic Compute Cloud (Amazon EC2) instance that facilitates one or multiple replication activities.
There is a range of various replication instances on offer and organizations can choose the best configuration for specific use cases. Use small instance classes for servicing minor volumes of data for migration or large instances where a greater number of tables or multiple concurrent replication tasks have to be run. This flexible approach is one of the strong points of the AWS database migration service. Replication tasks Creating a replication task has to be done before starting on data migration. The migration option has to be mentioned. Full load for migrating existing data is beneficial when systems can be shut down long enough to copy the entire data. Full load with Change Data Capture (CDC) should be used when, apart from migrating existing data, current changes too have to be replicated. Once the AWS database migration service completes the migration, the captured changes are applied to the target database. Finally, there is Change Data Capture where the data changes are replicated only after using an option other than the AWS database migration service.