Database Migration Service of AWS – Use Cases and Types

The Database Migration Service of Amazon Web Service (DMS AWS) is an optimized service based in the cloud. It facilitates seamless migration from on-premises databases to the cloud, two cloud providers, data warehouses, NoSQL databases, relational databases, data stores, and more. For DMS AWS to work, the pre-condition is that at least one of the databases among the source and the target should be in the cloud.

Working of the DMS AWS

With DMS AWS, users can either perform migration where entire databases are migrated at a time or prefer migration where all changes made at the source are continually migrated to the intended database. However, for the second method to take place, the source and the target databases should be kept in sync. By migrating with DMS AWS, businesses get all the benefits of the cloud such as enhanced database security, flexibility, and cost efficiencies.

By definition, it can be said that DMS AWS is a replication software that is a part of the AWS Cloud. The process of migration with this software starts with linking up the source and the target databases so that DMS knows from where the data has to be moved and to which point. The next step is to schedule a task that runs on the server that migrates the data.

If the required primary keys and the tables required for migration are not present in the target database, DMS AWS automatically creates them during the process. The user can also create the target tables, indexes, and triggers essential for migration with the AWS SCT (Schema Conversion Tool).

Types of Database Migration with DMS AWS

There are two methods of migration with DMS AWS.

Homogeneous Database Migration

In this type of migration, the source and the target database engines, data types and codes, and schema structures must be of a similar form. Migration here is a smooth and seamless activity with the source database being migrated to the target in one shot. A few examples where Homogeneous Migration is the ideal method is when this process is taken up between Oracle to Amazon RDS for Oracle, MySQL to Amazon Aurora, MySQL to Amazon RDS for MySQL, or Microsoft SQL Server to Amazon RDS for SQL Server.

Heterogeneous Database Migration

As distinct from the previous method, in this case, the engines of the source and the target databases, data types and codes, and schema structures have to be different. Hence, an extra step has to be done by the users as the schema structures and the data codes of the source database have to be transformed to match that of the target database with the AWS SCT. Once this step is done, migration can be carried out as usual. Examples of Homogeneous database migration are Oracle to Amazon Aurora, Oracle to PostgreSQL, or Microsoft SQL Server to MySQL migrations.