- A
The standby instance was not configured in a different zone
Why wrong: HA configuration requires standby in a different zone; if misconfigured, failover may not work, but that does not explain the original primary not resuming.
- B
The HA instance is using local SSD which is not durable
Why wrong: Cloud SQL HA uses regional persistent disk, not local SSD.
- C
The original primary instance is deleted after failover
Why wrong: The original primary is not deleted; it becomes the new standby instance.
- D
The original primary instance's disk is now in read-only mode
After failover, the original primary's disk is remounted as read-only to avoid split-brain. The instance must be recreated as a standby.
Question 170 of 980
PCD Practice Question: Design Scalable and Highly Available Cloud Database Solutions
This PCD practice question tests your understanding of design scalable and highly available cloud database solutions. 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.
An engineer is configuring Cloud SQL for PostgreSQL with HA. They notice that after a failover, the original primary instance does not automatically resume as a standby. What is the likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"primary"Why it matters: Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
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 original primary instance's disk is now in read-only mode
In Cloud SQL HA, after a failover, the original primary becomes a new standby using the same underlying disk. It does not create a new instance automatically. The disk is preserved, and the standby is recreated.
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.
- ✗
The standby instance was not configured in a different zone
Why it's wrong here
HA configuration requires standby in a different zone; if misconfigured, failover may not work, but that does not explain the original primary not resuming.
- ✗
The HA instance is using local SSD which is not durable
Why it's wrong here
Cloud SQL HA uses regional persistent disk, not local SSD.
- ✗
The original primary instance is deleted after failover
Why it's wrong here
The original primary is not deleted; it becomes the new standby instance.
- ✓
The original primary instance's disk is now in read-only mode
Why this is correct
After failover, the original primary's disk is remounted as read-only to avoid split-brain. The instance must be recreated as a standby.
Clue confirmation
The clue word "primary" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
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.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- 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 startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which PCD exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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Design Scalable and Highly Available Cloud Database Solutions — study guide chapter
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FAQ
Questions learners often ask
What does this PCD question test?
Design Scalable and Highly Available Cloud Database Solutions — This question tests Design Scalable and Highly Available Cloud Database Solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The original primary instance's disk is now in read-only mode — In Cloud SQL HA, after a failover, the original primary becomes a new standby using the same underlying disk. It does not create a new instance automatically. The disk is preserved, and the standby is recreated.
What should I do if I get this PCD question wrong?
Identify which PCD exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "primary". Asks for the main purpose or function, not a secondary benefit. Eliminate answers that describe side-effects or partial functions.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
Last reviewed: Jul 4, 2026
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.
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