AWS Database Migration Service — Types and Benefits

Amazon Web Service Database Migration Service (AWS DMS) is the most optimized method to facilitate migration between most-used commercial databases. The main advantage of AWS DMS is that the database at source remains fully functional during migration without downtime or temporarily shutting down the systems. Hence, AWS DMS is highly suitable for database migration by large or mid-sized organizations for whom downtime can be very inconvenient.

How does AWS DMS work?

There are two types of database migrations.

• Homogeneous database migration: How does AWS DMS work here? Homogeneous migration is a one-step process as both the source database and the target database engines are compatible. All parameters like data types, database codes, and schema structure that are essential for migration match each other. Examples of this migration type include 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: the source database and the target database engines are different and the parameters like schema structure, database codes, and the data types have to be entered individually. To automate this process, the AWS Schema Conversion Tool is used to convert the schema and the source code to match that of the target database. After this step, AWS DMS migrates data from the source to the target database. Examples include Oracle to Amazon Aurora, Oracle to PostgreSQL, or Microsoft SQL Server to MySQL migrations.

The above migration types are an answer to how does AWS DMS work.

Benefits of AWS DMS
There are several benefits of using AWS DMS for database migration.

• Additional drivers or applications need not be installed for making changes to the source database. Then, how does AWS DMS work? A few clicks on the AWS Management Console will kick-start the migration process. The full activity is automated and the task of handling the entire work through replicating changes made at the source database to the target database is monitored by DMS.

• Data changes at source are continuously replicated to the target database in real-time. Hence, systems involved in the migration are not required to be shut down for migration. The source database functions as usual and organizations can do without system downtime.

• AWS DMS supports popular commercial databases. This leads to seamless migration between on-premises databases to Amazon RDS, Amazon EC2, or Aurora as well as databases running on EC2 to RDS or vice versa. Data can also be migrated between text-based data, SQL, and NoSQL with AWS DMS.
How does AWS DMS work when the objective is not only to migrate data but replicate current and ongoing changes too? It is through Change Data Capture (CDC). Once the Full Load migration is completed by AWS DMS, the incremental changes are applied to the target database till the application of the changes reaches stable levels.