- A
Refactor the application to be stateless. Migrate the web server to App Engine and the database to Cloud SQL for PostgreSQL. Use Cloud Memorystore for session state.
Why wrong: Requires significant refactoring, and the company wants to minimize changes.
- B
Migrate the web server to Compute Engine and the database to Cloud Spanner. Use a global load balancer for the web server and Spanner for transactional consistency.
Why wrong: Cloud Spanner is complex and not a direct SQL Server replacement; may require application changes.
- C
Migrate the web server to Compute Engine with a managed instance group and internal load balancer. Migrate the database to Cloud SQL for SQL Server with high availability across zones.
Minimizes changes, provides HA, scaling, and managed database.
- D
Lift and shift both web and database servers to Compute Engine. Use a managed instance group with autoscaling for the web server and a standalone VM for the database. Configure persistent disks for data.
Why wrong: Database management overhead is high; no easy high availability or scaling.
Google PCA Design and plan a cloud solution architecture Practice Question
This PCA practice question tests your understanding of design and plan a cloud solution architecture. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is migrating a critical on-premises application to Google Cloud. The application consists of a frontend web server that handles user requests and a backend database server that stores session state and processed data. The application is stateful because session data is stored in memory on the backend server. The company wants to minimize downtime during migration and ensure that the application can scale horizontally in the future. The current on-premises architecture has the web server and database server on separate physical machines. The web server communicates with the database server via a private network. The company expects that after migration, the application will need to handle double the current traffic. They also need to ensure that the architecture is resilient to zone failures within a single region. They are considering using Compute Engine for both the web and database servers, but they are open to other Google Cloud services. They have a requirement that the database must be relational and support ACID transactions. The database currently uses Microsoft SQL Server, but they are willing to migrate to a different database engine if it reduces operational overhead and provides better scalability. The team has limited experience with Google Cloud and wants to minimize architectural changes. Which course of action should the company take?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"minimum / minimize"Why it matters: Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
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
Migrate the web server to Compute Engine with a managed instance group and internal load balancer. Migrate the database to Cloud SQL for SQL Server with high availability across zones.
Option C is correct because it preserves the existing stateful architecture by using Compute Engine with a managed instance group and internal load balancer for the web tier, and Cloud SQL for SQL Server with cross-zone high availability for the database. This minimizes architectural changes, supports horizontal scaling via the managed instance group, and provides zone-level resilience for the relational database with ACID transactions, meeting the requirement to handle double traffic while minimizing downtime.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Refactor the application to be stateless. Migrate the web server to App Engine and the database to Cloud SQL for PostgreSQL. Use Cloud Memorystore for session state.
Why it's wrong here
Requires significant refactoring, and the company wants to minimize changes.
- ✗
Migrate the web server to Compute Engine and the database to Cloud Spanner. Use a global load balancer for the web server and Spanner for transactional consistency.
Why it's wrong here
Cloud Spanner is complex and not a direct SQL Server replacement; may require application changes.
- ✓
Migrate the web server to Compute Engine with a managed instance group and internal load balancer. Migrate the database to Cloud SQL for SQL Server with high availability across zones.
Why this is correct
Minimizes changes, provides HA, scaling, and managed database.
Clue confirmation
The clue word "minimum / minimize" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Lift and shift both web and database servers to Compute Engine. Use a managed instance group with autoscaling for the web server and a standalone VM for the database. Configure persistent disks for data.
Why it's wrong here
Database management overhead is high; no easy high availability or scaling.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often choose a lift-and-shift option (D) thinking it minimizes changes, but they overlook the requirement for zone-level resilience, which a standalone VM cannot provide, or they incorrectly assume that Cloud Spanner (B) is the only option for ACID transactions at scale, ignoring that Cloud SQL for SQL Server meets the need with less complexity and no database engine migration.
Detailed technical explanation
How to think about this question
Cloud SQL for SQL Server with high availability uses a regional persistent disk and synchronous replication to a standby instance in a different zone, providing automatic failover within minutes during a zone outage. Managed instance groups with autoscaling distribute web server traffic across zones via an internal load balancer, using health checks to route only to healthy instances, which supports horizontal scaling without session affinity issues since session state remains on the database. This architecture leverages Compute Engine's custom machine types and sole-tenant nodes if needed, while Cloud SQL handles patching, backups, and replication, reducing operational overhead for the team.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
What to study next
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FAQ
Questions learners often ask
What does this PCA question test?
Design and plan a cloud solution architecture — This question tests Design and plan a cloud solution architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Migrate the web server to Compute Engine with a managed instance group and internal load balancer. Migrate the database to Cloud SQL for SQL Server with high availability across zones. — Option C is correct because it preserves the existing stateful architecture by using Compute Engine with a managed instance group and internal load balancer for the web tier, and Cloud SQL for SQL Server with cross-zone high availability for the database. This minimizes architectural changes, supports horizontal scaling via the managed instance group, and provides zone-level resilience for the relational database with ACID transactions, meeting the requirement to handle double traffic while minimizing downtime.
What should I do if I get this PCA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "minimum / minimize". Asks for the least resource use — fewest addresses, smallest subnet, lowest overhead. Eliminate over-provisioned options even if they would technically work.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
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Last reviewed: Jun 25, 2026
This PCA 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 PCA exam.
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