The answer is to create a snapshot of the disk, then create a new regional persistent disk from that snapshot, and attach it to the instance. This approach achieves a zero-downtime migration from zonal to regional persistent disk because Compute Engine supports live attachment and detachment of persistent disks; you can detach the original zonal disk and attach the new regional disk without stopping the running instance. The snapshot captures a point-in-time state, and the regional disk is created asynchronously, so the workload continues uninterrupted during the process. On the Google Professional Cloud Architect exam, this scenario tests your understanding of Compute Engine’s live disk operations and the snapshot-to-disk workflow for high-availability migrations. A common trap is assuming you must stop the instance to swap disks or that you need to copy data manually—neither is required. Memory tip: think “snap, swap, stay live”—snapshot the zonal disk, swap to the regional disk, and the instance stays running.
Google PCA Manage implementation of cloud architecture Practice Question
This PCA practice question tests your understanding of manage implementation of cloud architecture. 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 organization is running a stateful workload on Compute Engine with a single persistent disk. They want to migrate to a regional persistent disk for higher availability. The disk is 500 GB and currently 80% full. They need zero downtime during the migration. What is the recommended approach?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Create a snapshot of the disk, then create a new regional persistent disk from that snapshot, and attach it to the instance.
Option B is correct because creating a snapshot of the existing persistent disk and then creating a new regional persistent disk from that snapshot allows you to attach the new disk to the instance with zero downtime. The snapshot captures the disk state at a point in time, and the regional disk is created asynchronously; once available, you can detach the original disk and attach the regional disk without stopping the instance, as Compute Engine supports live disk attachment/detachment.
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.
✗
Attach a new regional disk to the instance and use RAID 1 mirroring.
Why it's wrong here
Regional disks cannot be attached to a zonal instance; the instance must be regional as well.
✓
Create a snapshot of the disk, then create a new regional persistent disk from that snapshot, and attach it to the instance.
Why this is correct
This is the recommended migration path; snapshot creation is the only downtime window.
Related concept
Read the scenario before looking for a memorised answer.
✗
Use rsync to copy data to a new regional disk while the instance is running.
Why it's wrong here
rsync requires consistent state; for an active disk, this could cause data inconsistency and downtime.
✗
Use gcloud compute disks resize to change the disk type to regional.
Why it's wrong here
Disk resize does not change disk type from zonal to regional.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that you can change a disk's type in-place using a resize or update command, but the only supported way to switch from zonal to regional is to create a new disk from a snapshot or image.
Detailed technical explanation
How to think about this question
Regional persistent disks replicate data synchronously across two zones in the same region, providing higher availability against zonal failures. The snapshot-based migration leverages incremental snapshots and the ability to attach a regional disk to an instance while it is running, as long as the instance is in one of the zones where the regional disk is replicated. A subtle behavior: the instance must be in the same region as the regional disk, and you must detach the original zonal disk before attaching the regional disk to avoid device name conflicts.
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.
TExam Day Tips
→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
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
Related glossary terms
Concepts from this question explained
These glossary pages explain the core terms tested in this PCA question in full detail.
Manage implementation of cloud architecture — This question tests Manage implementation of cloud architecture — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Create a snapshot of the disk, then create a new regional persistent disk from that snapshot, and attach it to the instance. — Option B is correct because creating a snapshot of the existing persistent disk and then creating a new regional persistent disk from that snapshot allows you to attach the new disk to the instance with zero downtime. The snapshot captures the disk state at a point in time, and the regional disk is created asynchronously; once available, you can detach the original disk and attach the regional disk without stopping the instance, as Compute Engine supports live disk attachment/detachment.
What should I do if I get this PCA question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
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.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.