Q42 - How to migrate databases to AWS? #aws #databasemigration #database #migration #cloudcomputing

AWS Database Migration Service (AWS DMS) is a managed migration and replication service that helps move your database and analytics workloads to AWS quickly, securely, and with minimal downtime and zero data loss. AWS DMS supports migration between 20-plus database and analytics engines, such as Oracle to Amazon Aurora MySQL-Compatible Edition, MySQL to Amazon Relational Database (RDS) for MySQL, Microsoft SQL Server to Amazon Aurora PostgreSQL-Compatible Edition, MongoDB to Amazon DocumentDB (with MongoDB compatibility), Oracle to Amazon Redshift, and Amazon Simple Storage Service (S3).

Use cases
Move to managed databases
Migrate from legacy or on-premises databases to managed cloud services through a simplified migration process, removing undifferentiated database management tasks.

Remove licensing costs and accelerate business growth
Modernize to purpose-built databases to innovate and build faster for any use case at scale for one-tenth the cost.

Replicate ongoing changes
Create redundancies of business-critical databases and data stores to minimize downtime and protect against any data loss.

Improve integration with data lakes
Build data lakes and perform real-time processing on change data from your data stores.

Homogeneous database migrations: In homogeneous database migrations, the source and target database engines are the same or are compatible, such as 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.

Since the schema structure, data types, and database code are compatible between the source and target databases, this kind of migration is a one-step process. You create a migration task with connections to the source and target databases, and then start the migration with the click of a button. AWS Database Migration Service takes care of the rest.

The source database can be located in your own premises outside of AWS, running on an Amazon EC2 instance, or an Amazon RDS database. The target can be a database in Amazon EC2 or Amazon RDS.

AWS DMS has a couple of options to perform homogeneous migrations. The first option is using built-in native database tooling to automatically migrate to the target database without the need to manage replication instances. It is best used to migrate all data types and secondary objects for MySQL and PostgreSQL migrations to Amazon Aurora and Amazon RDS as target engines. Alternative options, using AWS DMS Serverless or on-demand replication instances, are available for all other engines.

Heterogeneous database migrations: In heterogeneous database migrations, the source and target databases engines are different, such as in the case of Oracle to Amazon Aurora, Oracle to PostgreSQL, or Microsoft SQL Server to MySQL migrations.

In this case, the schema structure, data types, and database code of source and target databases can be quite different, requiring a schema and code transformation before the data migration starts.

That makes heterogeneous migrations a two-step process. First, use AWS DMS Schema Conversion to convert the source schema and code to match that of the target database. Then use the AWS Database Migration Service to migrate data from the source database to the target database. AWS DMS offers the option to use on-demand replication instances or AWS DMS Severless, which simplifies migrations by automating the time-consuming tasks of provisioning, monitoring, and scaling migration resources.

All required data types will be automatically converted during the migration. The source database can be outside of AWS on your own premises or a third-party database service, on an Amazon EC2 instance, or an Amazon database. Likewise, the target database can be outside AWS, on an EC2 instance, or a managed Amazon database and analytics service. See the list of supported source and target engines.