The answer is to stripe data across multiple local SSD volumes using RAID 0. This technique, known as RAID 0 striping, combines the storage and I/O capacity of several physical disks into a single logical volume, distributing read and write operations in parallel across all disks. By doing so, it dramatically increases aggregate IOPS and throughput without requiring a larger instance type, since local SSDs are physically attached to the host server and already offer low latency. On the Google Professional Cloud DevOps Engineer exam, this question tests your understanding of Compute Engine local SSD performance optimization, often appearing as a scenario where you must improve disk I/O without scaling the machine. A common trap is to assume adding more vCPUs or memory is the fix, but the key is leveraging parallelism through RAID 0. Memory tip: “RAID 0 = Read All In Parallel for Zero latency gains.”
PCDOE Optimizing service performance Practice Question
This PCDOE practice question tests your understanding of optimizing service performance. 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.
A company runs a stateful workload on Compute Engine with local SSDs. They need to improve disk I/O performance without changing the instance type. Which THREE actions should they take?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Stripe data across multiple local SSD volumes using RAID 0.
Option B is correct because striping data across multiple local SSD volumes using RAID 0 increases the aggregate I/O throughput and IOPS by distributing read and write operations across all disks in parallel. This directly improves disk I/O performance without changing the instance type, as local SSDs are physically attached to the host and offer the highest performance when combined.
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.
✗
Migrate to persistent SSD for better durability.
Why it's wrong here
Persistent SSDs have lower max IOPS per GB.
✓
Stripe data across multiple local SSD volumes using RAID 0.
Why this is correct
Increases throughput and IOPS.
Related concept
Read the scenario before looking for a memorised answer.
✓
Use a filesystem optimized for SSDs, such as ext4 with noatime and nodiratime options.
Why this is correct
Reduces unnecessary writes.
Related concept
Read the scenario before looking for a memorised answer.
✓
Ensure the instance is in the same zone as the application that accesses the disks.
Why this is correct
Avoids cross-zone latency.
Related concept
Read the scenario before looking for a memorised answer.
✗
Enable encryption for the local SSDs to reduce I/O overhead.
Why it's wrong here
Encryption adds CPU overhead.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Google Cloud often tests the misconception that persistent SSDs are always better for performance, but local SSDs provide lower latency and higher IOPS for stateful workloads, and striping them with RAID 0 is the key to maximizing I/O without changing the instance type.
Detailed technical explanation
How to think about this question
RAID 0 striping on local SSDs works by dividing data into blocks and writing them across multiple disks simultaneously, which linearly scales the maximum IOPS and throughput with the number of disks. For example, with four local SSDs each capable of 100,000 random read IOPS, RAID 0 can achieve up to 400,000 IOPS, but it provides no redundancy, so a single disk failure results in data loss. The noatime and nodiratime mount options in ext4 reduce metadata writes by disabling access time updates, which decreases write amplification and improves SSD performance.
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
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Optimizing service performance — This question tests Optimizing service performance — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Stripe data across multiple local SSD volumes using RAID 0. — Option B is correct because striping data across multiple local SSD volumes using RAID 0 increases the aggregate I/O throughput and IOPS by distributing read and write operations across all disks in parallel. This directly improves disk I/O performance without changing the instance type, as local SSDs are physically attached to the host and offer the highest performance when combined.
What should I do if I get this PCDOE 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.
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Question Discussion
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