AWS Database Migration Service (AWS DMS)

Why AWS Database Migration Service is Important:
AWS Database Migration Service (AWS DMS) is a crucial service for organizations looking to migrate their databases to AWS or between different database engines within AWS. It simplifies the migration process, reduces downtime, and minimizes the impact on the source database. AWS DMS enables businesses to modernize their database infrastructure, take advantage of the scalability and cost-efficiency of AWS, and ensure data continuity during the migration process.

What is AWS Database Migration Service?
AWS Database Migration Service is a fully managed service that helps users migrate databases to AWS quickly and securely. It supports both homogeneous migrations (e.g., Oracle to Oracle) and heterogeneous migrations (e.g., Oracle to Amazon Aurora). AWS DMS can migrate data from various sources, including on-premises databases, Amazon RDS instances, and even other cloud providers' databases. It supports a wide range of database engines, such as Oracle, Microsoft SQL Server, MySQL, MariaDB, and PostgreSQL.

How AWS Database Migration Service Works:
1. Source and Target Databases: Users define the source and target databases for the migration. The source database can be on-premises, on AWS, or in another cloud, while the target database is typically an AWS service like Amazon RDS, Amazon Aurora, or Amazon Redshift.
2. Replication Instance: AWS DMS uses a replication instance to perform the migration. This instance runs the necessary software to connect to the source and target databases, transfer data, and manage the migration process.
3. Migration Tasks: Users create migration tasks that specify the source and target databases, the tables to migrate, and any necessary transformations or filters. AWS DMS supports full load, change data capture (CDC), and full load + CDC migration types.
4. Data Transfer: During the migration, AWS DMS reads data from the source database and writes it to the target database. It handles data type conversions, table and schema creation, and ensures data integrity.
5. Monitoring and Troubleshooting: AWS DMS provides monitoring and logging capabilities to track the progress of migrations, identify any issues, and troubleshoot problems.

Exam Tips: Answering Questions on AWS Database Migration Service (AWS DMS)
1. Understand the supported source and target databases and the migration types (full load, CDC, full load + CDC).
2. Know the role of the replication instance and its sizing considerations.
3. Be familiar with the different migration tasks and their configuration options.
4. Understand how AWS DMS handles schema conversion, data type mapping, and transformations.
5. Know the monitoring and logging options available for tracking migration progress and troubleshooting issues.
6. Recognize scenarios where AWS DMS is the most suitable solution for database migrations, such as heterogeneous migrations or minimal downtime requirements.