Designing highly scalable, available, and reliable cloud-native applications →hardMultiple ChoiceObjective-mapped
PCD Practice Question: Designing highly scalable, available, and reliable cloud-native applications
A company running a high-traffic e-commerce platform on Google Cloud experiences occasional data loss in their Cloud SQL database during failover events. The database is configured with a failover replica in a different zone. What is the most likely cause of the data loss?
⚠ Common exam trap
The PCD exam often tests the distinction between synchronous and asynchronous replication in the context of failover replicas, where candidates mistakenly assume all replicas are synchronous by default or confuse failover replicas with read replicas.
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
✓
The database is using asynchronous replication to the failover replica.
Cloud SQL uses synchronous replication for failover replicas by default, ensuring that transactions are committed on both the primary and the replica before acknowledging the write. If asynchronous replication is configured, the replica may lag behind the primary, and during a failover, any transactions not yet replicated are lost. This is the most likely cause of data loss during failover events.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Automated backups are not enabled.
Why it's wrong here
Backups are separate from failover replication.
- ✓
The database is using asynchronous replication to the failover replica.
Why this is correct
Asynchronous replication may not have replicated the most recent transactions before failover.
- ✗
The failover replica is configured as a read replica instead of a failover replica.
Why it's wrong here
Read replicas cannot be promoted during failover.
- ✗
The database is not using regional persistent disks.
Why it's wrong here
Regional persistent disks provide durability but not synchronous replication between zones.
Visual reference
Go deeper
Related to this question
About these practice questions
One of 964 original PCD practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This PCD 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 PCD exam.