A 2 TB Oracle database in a company data centre is being moved to Amazon Aurora PostgreSQL. The business will accept a cutover window of a few minutes and no more. Which approach meets that?

AWS Certified Cloud Practitioner (CLF-C02), objective 3. Cloud technology and services medium

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The options

Correct AWS Database Migration Service, with schema conversion for the Oracle-to-PostgreSQL differences

Correct. DMS performs a full load and then keeps replicating changes, so the source stays in production while the target catches up. The outage is only the moment you stop writing to one and start writing to the other.

Not correct Export a dump file, copy it to Amazon S3 and import it into Aurora

Wrong for the stated window. The database is unavailable, or at least frozen, for the whole export, transfer and import — hours at best for 2 TB, and there is no way to shorten it below the slowest of the three.

Not correct Ship the data on an AWS Snowball device

Wrong. Snowball exists for moving very large datasets when the network is the constraint, which 2 TB is not. It also does nothing about keeping a live database synchronised while you wait for a lorry.

Not correct Use AWS Backup to back up the source and restore it into Aurora

Wrong. AWS Backup protects AWS resources on a schedule; it neither reaches into an on-premises Oracle database nor converts between database engines.

Why

AWS Database Migration Service moves the data and can go on replicating changes until you are ready to cut over, which is how migrations get short outages. When the source and target engines differ — Oracle to PostgreSQL here — the schema, stored procedures and data types also have to be translated, which is the AWS Schema Conversion Tool's job. A homogeneous move, Oracle to Oracle or MySQL to Aurora MySQL, needs DMS alone.

Where this comes from

Cited
AWS exam guide task statement 3.4

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