hardMultiple ChoiceObjective-mapped
Google ACE Practice Question: Designing a globally distributed application with…
A company is designing a globally distributed application with a web tier and a database tier that requires low-latency communication within the same region but can tolerate eventual consistency across regions. The database must be fully managed and scale globally. Which combination of networking and database is most appropriate?
⚠ Common exam trap
Google Cloud often tests the distinction between strong consistency (Spanner) and eventual consistency (Bigtable) in globally distributed systems, and the trap here is assuming that 'fully managed and scale globally' always means Spanner, ignoring the explicit requirement for eventual consistency.
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
✓
Global VPC with Cloud Bigtable
Cloud Bigtable is a fully managed, globally scalable NoSQL database that provides low-latency access within a region and eventual consistency across regions, making it ideal for the described workload. A Global VPC allows the web and database tiers to communicate privately and with low latency within the same region, while Bigtable's native replication handles cross-region eventual consistency without application complexity.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Global VPC with Cloud Spanner
Why it's wrong here
Cloud Spanner is a globally distributed relational database that offers external strong consistency and ACID transactions across regions, but that level of consistency is overkill when the application explicitly tolerates eventual consistency. The synchronous replication and Paxos-based consensus required to maintain strong consistency also increase latency and cost significantly, making it an expensive, heavyweight choice for this workload. While it would technically satisfy the global distribution requirement, it violates the cost and simplicity objectives that likely accompany the stated consistency tolerance.
- ✓
Global VPC with Cloud Bigtable
Why this is correct
Cloud Bigtable is a fully managed, highly scalable NoSQL wide-column database that is designed for low-latency, high-throughput operations and supports eventual consistency across replicas. It can be configured with multiple clusters in different regions, enabling global read and write access through a global VPC while remaining operationally simple and cost-effective. The data model and access patterns of a multi-tier application often align well with Bigtable's key-based lookups, making it the appropriate choice when strong relational semantics are not required.
- ✗
VPC peering with Cloud SQL
Why it's wrong here
VPC peering is a networking construct that enables private communication between VPCs, but it does not in any way change the regional scope of Cloud SQL. Cloud SQL is a regional managed relational database service (MySQL, PostgreSQL, or SQL Server) with no built-in mechanism for global replication or distributed writes; only cross-zone high availability and read replicas in the same region or via cross-region replication are supported. Thus, while VPC peering provides connectivity, the underlying database cannot deliver low-latency global access or scale horizontally across continents, so this combination fails the application's global distribution requirement.
- ✗
Shared VPC with Cloud Datastore
Why it's wrong here
Shared VPC provides centralized network administration and allows resources from multiple projects to use a common VPC network, but it does not contribute any database distribution capabilities. Cloud Datastore (Firestore in Datastore mode) does offer global scalability and can provide eventual consistency, but it is fundamentally a document/NoSQL store designed for serverless, mobile, and web applications, not necessarily for multi-tier applications with high-throughput, low-latency, and wide-column requirements. Additionally, its strong-consistency options are limited to a single region, meaning the eventual-consistency mode is the only way to get global behavior, which may not be as predictable or performant as Bigtable for this particular workload.
Go deeper
Related to this question
Learn chapter
Google Cloud Platform Overview
Key term
VPC
A Virtual Private Cloud (VPC) is a logically isolated section of a cloud provider's network where you can launch and manage resources like servers and databases with complete control over IP addressing, subnets, route tables, and security.
Key term
Region
A region is a distinct geographic location where a cloud provider operates multiple data centers that are connected by low-latency networks and provide cloud services.
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This ACE 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 ACE exam.