Database Migration Service of AWS DMS– Functions and Benefits

One of the most optimized cloud-based platforms to migrate on-premises databases to the cloud or from one cloud provider to another is the Database Migration Service of Amazon Web Service. You can either opt for one-time data migration or continual data replication between the source and the target database provided both are continuously kept in sync. There cannot be a better platform than AWS DMS to move data from data warehouses, relational databases, or NoSQL databases.

Functioning of AWS DMS

Being a cloud-based replication software, AWS DMS can only function if a link is established between the source and the target database to enable it to know from and to where the data has to move. The next task is to define the activity that will load the data from the source to the target.


The good thing for DBAs is that AWS DMS handles the complete migration process without the need for any human intervention, even when the keys and the tables needed for migration are not present in the target database. In such instances, users have to use the AWS SCT (AWS Schema Conversion Tool) for creating tables, indexes, views, and triggers in the target database. Hence, all the benefits of the cloud like security, data usage elasticity, cost-efficiency, and improvedperformances are available in the AWS DMS for migrating databases.

Data Migration with AWS DMS

Depending on the characteristics and the architecture, there are two ways to migrate databases with AWS DMS.

  • Homogeneous Database Migration: This migration type has to be implemented when the engines of the source and the target databases are the same.Also, the data types, the data codes, and the schema structures of the two must be similar. Homogeneous migration is a simple single-step process. After a link is created between the source and the target, the full database is migrated at one time.

However, for this process to be successful, the source database should either operate on an Amazon EC2 instance or an Amazon RDS database. It might even be located outside the AWS. Examples of AWS DMShomogeneous database migration are Oracle to Amazon RDS for Oracle, MySQL to Amazon RDS for MySQL, MySQL to Amazon Aurora, and Microsoft SQL Server to Amazon RDS for SQL Server.

  • Heterogeneous Database Migration: As distinct from the other method, heterogeneous migration is selected when the engines, the data types, the data codes, and the schema structures of the source and the target databases are different.

The migration process is done in two stages. First, the Schema Conversion Tool is used to convert the data code and the schema structure to a format that matches the architecture of the target database. Only after this stage is completed can AWS DMS start the actual migration.

For Heterogeneous Migration, the source database can either be on an Amazon EC2 instance or an Amazon RDS database located on-site or off-premises. Examples of heterogeneous migration are Oracle to PostgreSQL, Microsoft SQL Server to MySQL, and Oracle to Amazon Aurora.

For database migration with AWS DMS, you have to select one of these two methods that best suits your needs and the structure of the databases.

The Benefits of AWS DMS As a Database Migration Solution

Here are some of the benefits of AWS DMS as a database migration solution.

  • Traditionally, database migration has always been long-drawn and complex process requiring the installation of additional software and hardware, their configuration, and debugging of existing systems. On the other hand, cloud-based AWS DMSauto-deploys, manages, and monitors all necessary infrastructure, and starts migration in minutes once it is configured.
  • Unmatched flexibility and scalability are provided by AWS DMS. Users have the leeway to scale up and down in data storage as required. Additionally, whenever storage capacity is needed, the same can be downloaded instantly. Most importantly, payment is for resources used, unlike older processes where flat one-time fees had to be paid regardless of the quantum used.
  • The failover feature of AWS DMS is one of the primary reasons for organizations wanting to use this service. In the event of an outage during migration, AWS DMS automatically triggers secondary servers on-site or off-site and the migration is not disrupted. When the outage is resolved, AWS DMS works in the opposite direction, updating the primary server with all data and transactions that occurred in the break period. Migration is thus resumed without any loss of data or downtime.
  • The complete infrastructure for migration is handled byAWS DMS. This includes software patching, error reporting, and tracking the performance of the hardware and software.
  • By migrating with AWS DMS, users get the benefit of being on a more advanced and cost-effective database. This provides them with a large range of managed database services like Amazon Aurora or Amazon Relational Database Service. They can also avail low-cost storage platforms like Amazon Simple Storage Service or data warehouses that are on NoSQL and Amazon Redshift platforms such as Amazon DynamoDB.
  • Data security and data safety are strictly enforced by AWS DMS during migration. Data at the source is encrypted with the AWS Key Management Service while data in flight to the target database is secured with the Secure Socket Layer (SSL).
  • All the popular DBMS source database engines as well as several target database engines are supported by AWS DMS.Hence, users find it very easy to migrate databases regardless of the type of engines they run on.

These are some of the benefits that make AWS DMS the preferred option for database migration for organizations around the world. Optimize your database migration process with AWS DMS.