Exam AWS Certified Solutions Architect - Associate SAA-C03 topic 1 question 235 discussion

C : because we need SCT to convert from Oracle to PostgreSQL, and we need memory optimized machine for databases not compute optimized.

B. Use AWS DataSync for the initial migration. Use AWS Database Migration Service (AWS DMS) to create a full load plus change data capture (CDC) replication task and a table mapping to select all tables. This approach leverages AWS DataSync for the initial data migration, which is optimized for high-speed transfer of large amounts of data. Then, AWS DMS is used to create a replication task with full load plus change data capture (CDC), ensuring ongoing synchronization between the on-premises Oracle database and Amazon Aurora PostgreSQL. By selecting all tables, the migration process ensures that all applications can continue to read from and write to the database without interruption during the migration period.

Answer is C - AWS Schema Conversion Tool (AWS SCT) supports heterogeneous database migrations by automatically converting the source database schema and a majority of the custom code to a format compatible with the target database.

Has to be SCT + DMS for all the tables so C is the choice. Why do you need SCT? Read this: https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/migrate-data-from-an-on-premises-oracle-database-to-aurora-postgresql.html

Oracle -> PostgreSQL, we need SCT, thus A and B are out. D maps only "the largest tables" but we need all tables

Another reason to rule out D is because it states “a table mapping to select the largest tables”, whereas selecting all tables (as stated in option C) in the table mapping is necessary to ensure a comprehensive migration.

because we need SCT to convert from Oracle to PostgreSQL, and we need memory optimized machine for databases not compute optimized. A memory-optimized replication instance is recommended because the database has a high number of reads and writes. Memory-optimized instances are designed to deliver fast performance for workloads that process large data sets in memory.

because we need SCT to convert from Oracle to PostgreSQL, and we need memory optimized machine for databases not compute optimized. https://repost.aws/zh-Hant/knowledge-center/dms-optimize-aws-sct-performance

Oracle database to Amazon Aurora PostgreSQL = AWS Schema Conversion Tool High number of reads and writes = memory optimized replication instance

A memory-optimized replication instance is recommended because the database has a high number of reads and writes. Memory-optimized instances are designed to deliver fast performance for workloads that process large data sets in memory.

DataSync is for file-level synch, so A and B can be excluded. C is better than D because memory-optimized instances are recommended to handle the high number of reads and writes

why not a? only capture the change is sufficient

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The AWS SCT is used to convert the schema and code of the Oracle database to be compatible with Aurora PostgreSQL. AWS DMS is utilized to migrate the data from the Oracle database to Aurora PostgreSQL. Using a memory-optimized replication instance is recommended to handle the high number of reads and writes during the migration process. By creating a full load plus CDC replication task, the initial data migration is performed, and ongoing changes in the Oracle database are continuously captured and applied to the Aurora PostgreSQL database. Selecting all tables for table mapping ensures that all the applications writing to the same tables are migrated. Option A & B are incorrect because using AWS DataSync alone is not sufficient for database migration and data synchronization. Option D is incorrect because using a compute optimized replication instance is not the most suitable choice for handling the high number of reads and writes.

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DMS+SCT for Oracle to Aurora PostgreSQL migration https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/migrate-an-oracle-database-to-aurora-postgresql-using-aws-dms-and-aws-sct.html