Step 1: Create an Amazon DMS Replication Instance - Database Migration Guide
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Step 1: Create an Amazon DMS Replication Instance

To create an Amazon Database Migration Service (Amazon DMS) replication instance, see Creating a replication instance. Usually, the full load phase is multi-threaded (depending on task configurations) and has a greater resource footprint than ongoing replication. Consequently, it’s advisable to start with a larger instance class and then scale down once the task is in the ongoing replication phase. Moreover, if you intend to migrate your workload using multiple tasks, monitor your replication instance metrics and re-size your instance accordingly.

For this use case, we will migrate a subset (the Sales schema) of the AdventureWorks database, which is over 3 GB in size. Because we perform a heterogenous migration without many LOB columns, we can start with a compute optimized instance like c5.xlarge running the latest Amazon DMS engine version. We can later scale up or down based on resource utilization during task execution.


Scaling replication instance during full load and ongoing replication phases is usually based on CloudWatch metrics such as CPU, memory, I/O, and so on. Choosing the appropriate replication instance class and size depends on several factors such as number of tasks, table size, DML activity, size of transactions, Large Objects (LOB), and so on. This is out of scope for this walkthrough. To learn more about these topics, see Choosing replication instance types and Sizing a replication instance.

To create an Amazon DMS replication instance, do the following:

  1. Sign in to the Amazon Web Services Management Console, and open the Amazon DMS console.

  2. If you are signed in as an Amazon Identity and Access Management (IAM) user, you must have the appropriate permissions to access Amazon DMS. For more information about the permissions required, see IAM permissions.

  3. On the Welcome page, choose Create replication instance to start a database migration.

  4. On the Create replication instance page, specify your replication instance information.

    For This Parameter Do This


    Enter datalake-migration-ri. If you are using multiple replication servers or sharing a user, choose a name that helps you quickly differentiate between the different servers.


    Enter Migrate SQL Server to Amazon S3 data lake.

    Instance class

    Choose dms.c5.xlarge. Each size and type of instance class has increasing CPU, memory, and I/O capacity.

    Engine version

    Leave the default value, which is the latest stable version of the Amazon DMS replication engine.

    Allocated storage (GiB)

    Choose 50.


    Choose the virtual private cloud (VPC) in which your replication instance will launch. If possible, select the same VPC in which either your source or target database resides (or both).

    Multi AZ

    If you choose Yes, Amazon DMS creates a second replication server in a different Availability Zone for failover if there is a problem with the primary replication server.

    Publicly accessible

    If either your source or target database resides outside of the VPC in which your replication server resides, you must make your replication server policy publicly accessible.

  5. Choose Create.