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What is AWS Database Migration Service (AWS DMS)

What is AWS Database Migration Service (AWS DMS)

Amazon Web Services (AWS) is an Amazon cloud service that delivers services in the form of building blocks that can be used to design and deploy any sort of application in the cloud.

These services or building pieces are meant to interact with one another, resulting in sophisticated and highly scalable applications.

AWS is the largest and most vibrant community, with millions of active customers and tens of thousands of partners worldwide. Customers from practically every industry and size, including startups, corporations, and public sector organizations, are operating every possible use case on AWS. The AWS Partner Network (APN) comprises thousands of systems integrators that specialize in AWS services and tens of thousands of independent software vendors (ISVs) who modify their software to work on AWS.

Are you exploring a method to move your on-premise database to the cloud and get the benefits of the cloud, such as enhanced performance, a managed environment, and greater accountability in maintenance costs? Here’s a tutorial for you about the AWS Database Migration

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What is AWS Database Migration Service?

AWS Database Migration Service (DMS) is a controlled and autonomous service that enables rapid and safe database migration to the cloud from on-premise DB instances, databases, or databases running on AWS EC2 instances. You can manage, change, and transfer your AWS cloud configurations using it. The databases that are offered include Redshift, DynamoDB, ElasticCache, Aurora, Amazon RDS, and DynamoDB.

  • DMS may be used to migrate relational databases, data warehouses, NoSQL databases, and other varieties of database systems to the cloud.
  • AWS DMS facilitates as well homogeneous (Oracle to Oracle) and heterogeneous (Amazon Aurora to Oracle) database transformations..
  • The origin database is still accessible during the conversion, increasing performance.
  • The Amazon Web services Console may be used to administer the whole migration process.

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How does AWS Database Migration Service Work?

Moving information from one database to the next is made possible by AWS DMS, a controlled and automatic migration service. Integrating DMS to the endpoints(target and source) is the first step in the process . You must host one among your endpoints on an AWS service in order to use AWS DMS.

  • Consider AWS DMS to be a server that runs replication software within the AWS cloud. To tell AWS DMS where to extract and send the data, you must provide a source and a destination connection.
  • Planning a server-side procedure to migrate your data is now possible. AWS DMS will build the necessary tables and primary keys if they don’t already exist at the destination.
  • The target tables can also be created from scratch. Use of the AWS SCT (AWS Schema Conversion Tool) is possible to create the target tables, indexes, views, triggers, and other objects.
Working of AWS Database Migration Service
  • The process of AWS Database Migration begins with a connection to your data source, after which the service reads the information and gets it ready for the database target. After that, the data is imported into the target database.
  • It undergoes a full load migration, which entails transferring source data to the target. Any updates made to the tables being downloaded during higher loads are cached changes that are kept on the replicating server.
  • To keep the destination and source databases in sync, as soon as the entire load is complete, AWS DMS immediately begins applying the cached adjustments to the database.

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Components of AWS Database Migration Service

Before you initiate the migration to AWS DMS, you need to be aware of three components:

  • Replication instance
  • Source & Target Endpoints
  • Replication tasks
Replication tasks
  • Replication instance:
    • Replication instances are managed instances of the Amazon Elastic Compute Cloud (EC2) that hold one or more replication jobs.
    • A replication server doing several linked replication jobs is seen in the figure above.
  • Source & Target Endpoints:
    • To connect target and source databases and move data, the AWS DMS makes use of endpoints.
    • Depending on the database, the kind of endpoint will change, but all endpoints need the same data, including, engine type, credentials, encryption techniques, port number, server name,and endpoint type.
  • Replication Tasks:
    • The replication job is used to transport data from the source endpoint to the destination endpoint; this is where you specify which tables and schemas are migrated and when.
    • The replication task creation phase must be accomplished before initiating a migration.
    • When creating a replication job, you must also provide the migration type, the source and target endpoints, and the replica instance to use.

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Use Cases of AWS DMS

Data Migration Service supports migration to Amazon RDS, Aurora, Redshift, DynamoDB, and DocumentDB. There are multiple application cases for AWS Database Migration Service, among which are detailed below:

1. Migration of a Homogeneous Database

Homogeneous database migration occurs when the target and source databases are identical or consistent with one another, such as MySQL to AWS RDS for MySQL, MySQL to Amazon Aurora MySQL to Amazon Aurora, Oracle to Amazon RDS for Oracle, or Microsoft SQL Server to Amazon RDS for SQL Server. It is a one-step method since the schema structure and data types of the target and source databases are consistent

AWS Database Migration Service Cases

2. Migration of Heterogeneous Databases

  • When the target and source database engines are diverse, such as when moving from Oracle to PostgreSQL, Oracle to Amazon Aurora, or Microsoft SQL Server to MySQL, this is known as heterogeneous database migration.
  • A schema and code transformation is necessary prior to migration since the source and target databases’ schema structures and data types differ. This makes migration a two-step procedure.

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Benefits of AWS Database Migration Service

  • AWS DMS is serverless and can deploy, maintain, and monitor all hardware and software required for migration automatically, allowing you to eliminate traditional duties such as capacity analysis, hardware, and software procurement, system installation and administration, and system testing/debugging. Technically, your transfer may begin within minutes after AWS DMS configuration.
  • Oracle, Microsoft SQL Server, PostgreSQL, MySQL, Amazon Redshift, SAP ASE, Amazon S3, and Amazon DynamoDB are among the targets supported by AWS DMS.
  • Minimal downtime – DMS constantly transfers the modifications to your data source during the migration process while keeping it functioning. As a result, you can change databases at any time without having to shut down.
  • Reliability – Database Migration Service is a self-healing service that, in the event of an interruption, will start again right away. For disaster recovery, DMS enables you to configure Multi-AZ (availability zone) replica.
  • Supports Most Notable Databases – Your data may be moved across the most well-liked corporate and accessible databases with the help of AWS Database Migration Service.
  • Low cost – Data Migration Service is a free migration solution for switching to DocumentDB, Redshift, Aurora, or DynamoDB. You must pay for other databases based on the volume of log storing and the computational load.

Limitations of AWS DMS

  • Problems with AWS DMS Schema Migration and Conversion:

AWS DMS does not typically perform schema or code conversion. When transferring data as part of a homogeneous migration, AWS DMS attempts to construct a target schema at the destination. This isn’t always possible, like with Oracle databases.

To generate schema, you may need to use third-party tools. In the case of heterogeneous migrations, AWS DMS cannot perform schema conversions; instead, the AWS Schema Conversion Tool must be used (SCT). This allows you to convert your source schema to a format suited for your destination; however, not all formats are supported. If the tool does not support your format, conversions must be done manually. This is one of the most essential.

  • Coding requirements for incremental data capture

Change Data Capture of incremental loads in AWS DMS requires some code, which may be time-consuming and labor-intensive. For example, with S3, updates must be integrated using specific code.

  • Performance

AWS DMS can load 8 tables in parallel by default. When utilizing a very big replication server, this may assist performance to some extent. However, if the source creates high throughput data, the replication may be delayed.


I think you now have a thorough understanding of AWS Database Migration Service’s functions, capabilities, and structure. This should help you get beyond the challenging issues with moving databases to AWS.

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