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Difficulty: Very hardDatabase Migration and Schema Conversion using DMS and SCT

An enterprise is migrating a self-managed, on-premises Oracle 19c database containing tables with Transparent Data Encryption (TDE) enabled and several tables with Large Objects (LOBs) up to 150 KB to an Amazon Aurora PostgreSQL-Compatible Edition DB cluster. The migration must minimize downtime, and the database experiences high write volumes. A solutions architect is designing the AWS Schema Conversion Tool (SCT) and AWS Database Migration Service (DMS) configuration. Which of the following actions should the Solutions Architect perform to meet these requirements? (Select two.)

  1. Configure the AWS DMS source database endpoint to use the Binary Reader method instead of Oracle LogMiner, and specify the path to the Oracle wallet containing the Transparent Data Encryption (TDE) keys in the endpoint settings.Answer
  2. Configure the AWS DMS replication task to use Limited LOB mode and set the maximum LOB size to 150 KB to ensure that LOB data is transferred in a single pass without querying the source database.Answer
  3. C
    Configure the AWS DMS replication task to use Full LOB mode and configure the LOB chunk size to 150 KB to optimize the multi-pass data retrieval process for highly active tables.
  4. D
    Enable supplemental logging on the target Aurora PostgreSQL DB cluster for the schema columns containing LOBs and encrypted data to ensure data integrity during replication.
  5. E
    Deploy the AWS Schema Conversion Tool (SCT) extraction agent on a dedicated replication instance and configure it to continuously stream TDE-encrypted transaction changes from the Oracle LogMiner interface.

Answer

To migrate the database successfully with TDE and LOBs under high write volumes, you must configure the AWS DMS source endpoint to use the Binary Reader method with the Oracle wallet path for TDE decryption, and set the DMS replication task to use Limited LOB mode with a maximum size of 150 KB.
The correct actions involve configuring the AWS DMS source database endpoint to use the Binary Reader method and using Limited LOB mode on the replication task. The Binary Reader method is required for AWS DMS to read and decrypt Transparent Data Encryption (TDE) protected redo logs directly from the source Oracle file system or ASM, which avoids LogMiner overhead. Limited LOB mode with a maximum size of 150 KB ensures that LOB data is fetched in a single-pass select statement along with the rest of the row, preventing the secondary query lookup per row that Full LOB mode requires, thereby preserving performance on high write volume databases.

Step-by-Step Solution

1
Analyze the database migration requirements for TDE encryption and LOB data under high write volumes.
Identified that LogMiner is not suitable for TDE decryption under high volumes and that Full LOB mode causes replication lag.
Guides the architecture selection towards Binary Reader and Limited LOB mode.
2
Configure the AWS DMS source endpoint for the Oracle database.
Set the CDC method to Binary Reader and provided the Oracle wallet path for TDE decryption.
Enables AWS DMS to read and decrypt active and archived redo logs directly from the file system or ASM.
3
Configure the AWS DMS replication task settings for LOB handling.
Configured Limited LOB mode with a maximum size of 150 KB.
Ensures LOB data is transferred in a single pass without secondary queries, avoiding performance degradation under high write volumes.

Key Concept

AWS DMS Oracle source CDC configuration with TDE and LOB optimization
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Topics

Database Migration and Schema Conversion using DMS and SCT

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