Google PCA Design and plan a cloud solution architecture Practice Question
An online retailer is deploying a new order-processing system on Google Cloud. The system consists of a regional managed instance group (MIG) of Compute Engine VMs that read from and write to a Cloud SQL for MySQL instance. The database must tolerate the loss of an entire zone within the region with minimal downtime and no manual failover steps, while keeping costs predictable. Which Cloud SQL configuration should the architect recommend?
⚠ Common exam trap
The trap here is assuming that automated backups or a cross-region read replica provide automatic zone failover, when only Cloud SQL high availability does.
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
✓
A Cloud SQL instance configured with high availability (regional) and a standby instance in a second zone.
Zone-level resilience for Cloud SQL comes from high availability mode, which maintains a standby in a separate zone and performs automatic failover without operator intervention. Read replicas address regional disasters and require manual promotion, while zonal deployments and vertical scaling leave the database exposed to a single-zone failure. The regional HA configuration matches the availability and operational requirements at a predictable cost.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
A Cloud SQL read replica in a second region that the application promotes to primary during an outage.
Why it's wrong here
A cross-region read replica protects against a full regional failure, not a zone failure, and promotion is a manual operation that changes the connection endpoint. It also introduces asynchronous replication lag, so recent writes can be lost. This scenario needs automatic, in-region zone failover rather than a manually promoted remote replica.
- ✗
A zonal Cloud SQL instance with automated backups and binary logging enabled, restored manually during an outage.
Why it's wrong here
A zonal instance runs in a single zone, so a zone outage takes the database offline until an operator restores a backup, which is not minimal downtime and requires manual action. Automated backups and binary logging help with point-in-time recovery after data loss, but they do not provide automatic failover within the region. This fails the availability and no-manual-failover requirements.
- ✗
A Cloud SQL instance with a larger machine type and increased storage to improve throughput and resilience.
Why it's wrong here
Resizing a machine type or adding storage improves performance and capacity but does not change the underlying fault domain. A single zonal instance remains unavailable if its zone fails, and no automatic failover occurs. Vertical scaling addresses throughput problems, not the stated requirement to survive the loss of an entire zone with minimal downtime.
- ✓
A Cloud SQL instance configured with high availability (regional) and a standby instance in a second zone.
Why this is correct
Cloud SQL high availability provisions a standby instance in a different zone and synchronously replicates to it. If the primary zone fails, Cloud SQL automatically promotes the standby, so the application reconnects with minimal downtime and no manual steps. This directly satisfies the zone-failure tolerance and predictable cost of a single regional instance pair.
Go deeper
Related to this question
Learn chapter
Google Kubernetes Engine (GKE)
Key term
Compute Engine
Compute Engine is Google Cloud's Infrastructure-as-a-Service (IaaS) offering that lets you create and run virtual machines on Google's infrastructure.
Key term
High availability
High availability is a system design approach that aims to keep applications and services operational and accessible with minimal downtime, even when some components fail.
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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.