Google PCA Design and plan a cloud solution architecture Practice Question
A retail company is deploying a customer-facing API on Google Cloud. The API must survive the loss of an entire region with minimal data loss and must serve users in North America, Europe, and Asia with low latency. The database layer must support strongly consistent reads and writes. Which design should the architect choose for the data tier?
⚠ Common exam trap
The trap here is assuming that cross-region read replicas on a single-primary database provide both regional failover and strongly consistent reads at global scale.
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
✓
Cloud Spanner with a multi-region instance configuration, with application instances reading and writing through regional endpoints.
Cloud Spanner is the Google Cloud database that provides synchronous multi-region replication with external consistency, so losing a region does not lose committed writes and reads stay strongly consistent. Regional endpoints let each continent's application instances talk to nearby replicas while the multi-region quorum maintains durability and correctness.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Firestore in Datastore mode with a multi-region location and client-side caching of query results.
Why it's wrong here
Firestore in Datastore mode offers strong consistency for single-entity reads but its query semantics and transaction limits differ from a relational API, and it does not provide the SQL interface or multi-region synchronous replication guarantees the scenario implies. It is also a poor fit for complex relational access patterns.
- ✗
Bigtable with a multi-cluster routing policy and application-level retries for failed writes.
Why it's wrong here
Bigtable is a wide-column NoSQL store with strong consistency only within a single cluster; multi-cluster replication is eventually consistent across clusters. Application retries do not make cross-cluster writes strongly consistent, so this cannot meet the requirement.
- ✓
Cloud Spanner with a multi-region instance configuration, with application instances reading and writing through regional endpoints.
Why this is correct
Cloud Spanner's multi-region configurations replicate synchronously across regions with external consistency, so a region loss does not lose committed data and reads remain strongly consistent. Serving from regional endpoints keeps latency low for users on each continent while the multi-region quorum preserves durability.
- ✗
A single Cloud SQL for PostgreSQL instance in us-central1 with cross-region read replicas in europe-west1 and asia-east1.
Why it's wrong here
Cross-region read replicas improve read latency but the primary remains a single point of failure in one region, and replicas are eventually consistent, so strongly consistent reads must go back to the primary across an ocean. This fails both the region-loss and latency requirements.
Go deeper
Related to this question
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Virtual Machine Instances in Compute Engine
Key term
Spanner
Google Cloud's globally distributed, strongly consistent, and horizontally scalable database service designed for mission-critical, transactional workloads.
Key term
Multi-region
Multi-region refers to a deployment strategy where IT resources, applications, or data are hosted in multiple geographic locations to improve availability, disaster recovery, and performance.
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JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Google Cloud exam blueprint
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.