1Z0-997-25 Question 76
Select 2You are migrating a mission-critical, 10 TB Oracle database from on-premises to OCI and need to minimize downtime without compromising data integrity. Which TWO methods are recommended to achieve minimal downtime and maintain data consistency throughout the migration?
- A
Use Oracle Data Pump for a full export/import of the database
- B
Leverage Oracle GoldenGate for near real-time replication
- C
Manually copy data files to an OCI block volume and recreate the control file
- D
Use Oracle Zero Downtime Migration (ZDM) to orchestrate a near-zero downtime migration
- E
Employ an offline RMAN backup and restore strategy with no additional replication mechanism
Show answer and explanation
Correct answers: B, D
Explanation
Oracle GoldenGate and Zero Downtime Migration (ZDM) are commonly recommended for migrating large on-premises databases to OCI while maintaining data consistency and minimizing downtime. GoldenGate replicates ongoing transactions in near real-time, whereas ZDM automates and streamlines various migration approaches (including GoldenGate or Data Pump under the covers) for a more seamless process. For more details and best practices, refer to the Oracle Cloud Infrastructure documentation on Database Migration and Zero Downtime Migration.
- A. Incorrect.
Option 1: INCORRECT. While Oracle Data Pump is straightforward, it generally requires significant downtime for large databases. You must complete the export before initiating the import, during which the source database can't be fully active without risking data consistency issues.
- B. Correct.
Option 2: CORRECT. Oracle GoldenGate enables near real-time replication of changes from your on-premises database to the target database on OCI. This approach greatly reduces downtime as you can keep your target database consistently updated until final switchover.
- C. Incorrect.
Option 3: INCORRECT. Manually copying data files and recreating the control file is error-prone, and you cannot maintain data changes during the copy. This method also doesn't address near-zero downtime requirements.
- D. Correct.
Option 4: CORRECT. Oracle Zero Downtime Migration (ZDM) is specifically designed to migrate critical Oracle databases to OCI with minimal downtime. It automates and orchestrates migration steps, including data transfer and synchronization, ensuring minimal disruption.
- E. Incorrect.
Option 5: INCORRECT. An offline RMAN backup and restore strategy provides no means of continuous data replication. You must take the source database offline (or significantly restrict access) to make a consistent backup, leading to noticeable downtime.