PCDE Migrate data solutions Practice Question
An organization is migrating a 500 GB Oracle database to Cloud SQL for PostgreSQL using DMS with continuous CDC. The migration is in progress, and the team needs to ensure that if the migration fails, they can roll back with minimal data loss. Which two pre-migration steps should they take? (Choose 2)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Take a full backup of the source database before starting the migration.
A rollback plan should include keeping the source running (read-only during cutover) and taking a full backup before migration. Exporting from the target is not helpful for rollback. Setting up a replica on-premises is unnecessary.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Take a full backup of the source database before starting the migration.
Why this is correct
Backup ensures point-in-time recovery for rollback.
- ✗
Export the Cloud SQL for PostgreSQL schema before migration.
Why it's wrong here
Not helpful for rollback to Oracle.
- ✗
Configure DMS to allow writes to the source after promotion.
Why it's wrong here
DMS does not control source writes; source should be read-only during cutover.
- ✗
Set up an Oracle Data Guard replica on-premises.
Why it's wrong here
Overkill; a backup is sufficient.
- ✓
Keep the source Oracle database running and accepting writes until cutover.
Why this is correct
Source remains available for rollback if needed.
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Variation 1. A company is migrating a 5 TB Oracle database to Cloud SQL for PostgreSQL using DMS with continuous migration. They need to minimize downtime and have a rollback plan. Which TWO actions should they include in their migration plan? (Choose TWO.)
medium- A.Use a one-time migration job instead of continuous.
- ✓ B.Test the application against the destination Cloud SQL instance before cutover.
- C.Delete the source database immediately after promoting the destination.
- D.Skip schema conversion and use raw Oracle SQL.
- ✓ E.Keep the source database running in read-only mode for a period after cutover.
Why B: A rollback plan involves keeping the source available in read-only mode for a validation window. Testing the application against the destination also validates the migration before cutover.
Variation 2. An organization is migrating a MySQL database to Cloud SQL using DMS with continuous replication. After promoting the destination, they need a rollback plan. Which approach should they use to enable a quick rollback if issues arise?
medium- A.Delete the source database immediately after promotion.
- B.Take a snapshot of the source database before promotion.
- ✓ C.Keep the source database running in read-only mode for a few days.
- D.Enable binary logging on the Cloud SQL instance after promotion.
Why C: A rollback plan should keep the source database running but read-only for a validation window. This allows switching back if needed without data loss.
Variation 3. After promoting a Cloud SQL destination in a DMS continuous migration, the application team updates the connection strings. However, they want a rollback plan in case issues arise. What should they keep running to allow a rollback?
easy- A.Keep both databases writable
- B.Keep the destination database in read-only mode
- C.Keep the DMS job active
- ✓ D.Keep the source database running in read-only mode
Why D: Keeping the source database running (read-only) allows reverting to it if needed. The DMS job is stopped after promotion. The destination is now the primary. Keeping both writable could cause conflicts.
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCDE practice question is part of Courseiva's free Google Cloud certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the PCDE exam.