AWS Database Migration Service (AWS DMS) is a managed and automated service that helps you migrate your databases from your on-premises or cloud environment to AWS, either as a one-time migration or as a continuous replication. AWS DMS supports migration between 20-plus database and analytics engines, such as PostgreSQL, Oracle, MySQL, SQL Server, MongoDB, Amazon Aurora, Amazon RDS, Amazon Redshift, and Amazon S3. AWS DMS also provides schema conversion and validation tools, as well as monitoring and security features. AWS DMS is a cost-effective and reliable solution for database migration, as you only pay for the compute resources and additional log storage used during the migration process, and you can minimize the downtime and data loss with Multi-AZ and ongoing replication12

To migrate a PostgreSQL database from on-premises to Amazon RDS using AWS DMS, you need to perform the following steps:

Create an AWS DMS replication instance in the same AWS Region as your target Amazon RDS PostgreSQL DB instance. The replication instance is a server that runs the AWS DMS replication software and connects to your source and target endpoints. You can choose the instance type, storage, and network settings based on your migration requirements3

Create a source endpoint that points to your on-premises PostgreSQL database. You need to provide the connection details, such as the server name, port, database name, user name, and password. You also need to specify the engine name as postgres and the SSL mode as required4

Create a target endpoint that points to your Amazon RDS PostgreSQL DB instance. You need to provide the connection details, such as the server name, port, database name, user name, and password. You also need to specify the engine name as postgres and the SSL mode as verify-full.

Create a migration task that defines the migration settings and options, such as the replication instance, the source and target endpoints, the migration type (full load, full load and change data capture, or change data capture only), the table mappings, the task settings, and the task monitoring role. You can also use the AWS Schema Conversion Tool (AWS SCT) to convert your source schema to the target schema and apply it to the target endpoint before or after creating the migration task.

Start the migration task and monitor its progress and status using the AWS DMS console, the AWS CLI, or the AWS DMS API. You can also use AWS CloudFormation to automate the creation and execution of the migration task.

The other options are not suitable for migrating a PostgreSQL database from on-premises to Amazon RDS. Cloud Adoption Readiness Tool is a tool that helps you assess your readiness for cloud adoption based on six dimensions: business, people, process, platform, operations, and security. It does not perform any database migration tasks. AWS Migration Hub is a service that helps you track and manage the progress of your application migrations across multiple AWS and partner services, such as AWS DMS, AWS Application Migration Service, AWS Server Migration Service, and CloudEndure Migration. It does not perform any database migration tasks itself, but rather integrates with other migration services. AWS Application Migration Service is a service that helps you migrate your applications from your on-premises or cloud environment to AWS without making any changes to the applications, their architecture, or the migrated servers. It does not support database migration, but rather replicates your servers as Amazon Machine Images (AMIs) and launches them as EC2 instances on AWS.

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