Database Migration with DMS AWS

When you want to migrate on-premises databases to the cloud or from one cloud provider to another, there is no better service than DMS AWS (Database Migration Service of Amazon Web Service). There are two options before businesses to do so. The first is one-time migration of databases and the second is continuous replication of data between the source and the target databases provided both are kept in sync. With this service from Amazon, you can move data from data warehouses, NoSQL databases, or relational databases.

Working of DMS AWS

Since DMS AWS is a cloud-based replication software it can only function if a link is established between the source and the target databases. This is to identify the databases from where the data will be moved and to which location. Next, it has to be defined which activity will load the data from the source to the target. What goes a long way to facilitate migration with DMS AWS is that the process is fully automated and there is no need for human intervention by DBAs.

This is even when the tables and the keys that are needed for migration are not there in the target database. However, the only deviation from the normal process in such cases is that users have to use the AWS Schema Conversion Tool (AWS SCT) for creating indexes, views, tables, and triggers in the target database. All the advantages of a cloud platform like data usage elasticity, cost-efficiency, security, and improved database performance are available when databases are migrated with DMS AWS.

Data Migration Process with DMS AWS

You can migrate databases with DMS AWS in two ways.

Homogeneous Database Migration

This method is ideal when the database engines, the data types, the data codes, and the schema structures of both the source and the target databases are the same. Migration here is a simple one-step process and can be initiated once the source and the target databases are linked. The source database can either be based on an Amazon EC2 instance or located outside the AWS or on an Amazon RDS database. The target database can be an Amazon EC2 instance or an Amazon RDS.

The most frequently-used instances of homogeneous migration are MySQL to Amazon Aurora, Microsoft SQL Server to Amazon RDS for SQL Server, Oracle to Amazon RDS for Oracle, MySQL to Amazon RDS for MySQL.

Heterogeneous Database Migration

DMS AWS is deployed for heterogeneous migration when the data types, data codes, schema structures,and the database engines of the source and the target are different. This process is a two-step one. First, the schema structure and the data code of the source database have to be converted to match the architecture of the target database. Only then can the migration be started.

Organizations can choose any one of the two depending on the structure of the databases.