A data analysis engineer has an old on-premise database for his meteorology analysis for years. This database is growing too big and becoming less responsive. He prefers to migrate it to AWS DynamoDB, and he already has the mapping rules in place. However, he has been told that the database type is unsupported by AWS Database Migration Service. He can export the data to CSV format files from the old database. How can the data analysis engineer migrate the data to AWS DynamoDB successfully?

Answer options:

A.Firstly, upload the CSV files to S3. Create an S3 source endpoint and DynamoDB target endpoint in AWS DMS. Create a migration task by referring to the source and target endpoints. Add the mapping rule in the task using a JSON format.
B.AWS Database Migration Service is inappropriate for this task. Upload the CSV files to S3 and then use an AWS Data Pipeline to import the data from S3 to DynamoDB by an S3-to-DynamoDB template.
C.Upload the exported CSV files to S3 at first. Then create S3 source endpoint and DynamoDB target endpoint in AWS DMS console. When the S3 source endpoint is configured, add the table mapping rule with a JSON table structure. Create a Replication Task to move the data from the source endpoint to the target endpoint.
D.AWS Database Migration Service is not needed for this scenario. The AWS DynamoDB supports the import of CSV Excel files directly by console and CLI. Create the DynamoDB table firstly with a proper schema and then import the CSV database data.

Correct Answer – C
 
In most cases, when someone is migrating to a new database, he has access to the source database and can use the database directly as a source. Sometimes, however, he might not have access to the source directly. In other cases, the source is really old or possibly unsupported. In these cases, if he can export the data in CSV format, he can still migrate or platform, the data. In this question, DMS does not support this database type. However, the CSV files can be used after being uploaded to S3. AWS Database Migration Services (AWS DMS) added support for using Amazon S3 as a source for database migration.
If S3 is the source endpoint, an external table definition is required. An external table definition is a JSON document that describes how AWS DMS should interpret the data from Amazon S3. The maximum size of this document is 2 MB. If a source endpoint is created using the AWS DMS Management Console, a JSON file can be entered directly into the table mapping box such as:
Option A is incorrect: Because the mapping rule should be put in the source endpoint configuration rather than the task settings if S3 is the source for DMS.
Option B is incorrect: Because AWS Database Migration Service is suitable. Moreover, Data Pipeline does not deal with the table mappings. Data Pipeline is suitable for data backup instead of database migration.
Option C is CORRECT: It correctly describes how to use S3 as the source endpoint and defines the mapping rules. Below is a piece of JSON mapping rule:
A reference is in https://aws.amazon.com/blogs/database/migrate-delimited-files-from-amazon-s3-to-an-amazon-dynamodb-nosql-table-using-aws-database-migration-service-and-aws-cloudformation/.
Option D is incorrect: Because DynamoDB cannot resolve the table mapping by uploading CSV files exported from databases. Data Migration Service can deal with this scenario properly.