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Ensure solution and operations reliability →hardMultiple ChoiceObjective-mapped

Quick Answer

The answer is the default node pool uses pd-standard disks, which have low IOPS. This is the most likely cause of high latency because pd-standard disks are backed by hard disk drives (HDDs) and offer significantly lower input/output operations per second compared to pd-ssd or local SSDs, creating a bottleneck for any application requiring high disk I/O performance. On the Google Professional Cloud Architect exam, this scenario tests your understanding of GKE default node pool configurations and the performance characteristics of persistent disk types; a common trap is assuming the default is sufficient for production workloads. Remember that GKE’s default node pool always provisions pd-standard for cost efficiency, not performance. For a quick memory tip: “Standard is slow, SSD is speed” — if your app needs high IOPS, never settle for the default pd-standard.

Google PCA Ensure solution and operations reliability Practice Question

This PCA practice question tests your understanding of ensure solution and operations reliability. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.

Exhibit

Refer to the exhibit.

```
$ gcloud container clusters describe my-cluster --region us-central1
...
nodePools:
- config:
    diskSizeGb: 100
    diskType: pd-standard
    imageType: COS_CONTAINERD
    machineType: n1-standard-2
    oauthScopes:
    - https://www.googleapis.com/auth/devstorage.read_only
  initialNodeCount: 3
  management:
    autoRepair: true
    autoUpgrade: true
  name: default-pool
...
```

You are running a Kubernetes cluster in GKE with the default node pool configuration shown in the exhibit. Your application requires high disk I/O performance. You notice that the application is experiencing high latency for disk operations. What is the most likely cause?

Clue words in this question

Noticing these words before you look at the options changes how you read each choice.

  • Clue: "most likely"

    Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

Question 1hardmultiple choice
Full question →

Exhibit

Refer to the exhibit.

```
$ gcloud container clusters describe my-cluster --region us-central1
...
nodePools:
- config:
    diskSizeGb: 100
    diskType: pd-standard
    imageType: COS_CONTAINERD
    machineType: n1-standard-2
    oauthScopes:
    - https://www.googleapis.com/auth/devstorage.read_only
  initialNodeCount: 3
  management:
    autoRepair: true
    autoUpgrade: true
  name: default-pool
...
```

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 default node pool uses pd-standard disks, which have low IOPS.

The default node pool in GKE uses pd-standard (standard persistent disk) which provides lower IOPS compared to pd-ssd. For applications requiring high disk I/O performance, pd-standard disks become a bottleneck, causing high latency. Upgrading to pd-ssd or using local SSDs would resolve this issue.

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.

  • ✗

    Node auto-repair is causing disk contention.

    Why it's wrong here

    Node auto-repair fixes unhealthy nodes, it does not cause disk contention.

  • ✓

    The default node pool uses pd-standard disks, which have low IOPS.

    Why this is correct

    pd-standard is HDD with lower IOPS; pd-ssd provides higher performance for high I/O workloads.

    Clue confirmation

    The clue word "most likely" in the question point toward this answer.

    Related concept

    Read the scenario before looking for a memorised answer.

  • ✗

    The OAuth scopes restrict disk access, causing high latency.

    Why it's wrong here

    The scopes allow read-only access to Cloud Storage, which is not related to persistent disk latency.

  • ✗

    The machine type n1-standard-2 does not have enough CPU.

    Why it's wrong here

    CPU is not the bottleneck; the issue is disk I/O performance.

Common exam traps

Common exam trap: answer the scenario, not the keyword

Google Cloud often tests the distinction between storage performance (disk type) and other operational features (auto-repair, scopes, machine type), leading candidates to confuse node health mechanisms or permission settings with actual I/O performance bottlenecks.

Detailed technical explanation

How to think about this question

GKE default node pools use pd-standard (backed by HDD) with a baseline IOPS of ~0.75 per GB and burst capability up to 3000 IOPS for 30 minutes per day. In contrast, pd-ssd provides a baseline of 30 IOPS per GB with no burst limits. For sustained high I/O workloads, pd-standard quickly exhausts its burst credits, causing latency spikes. Real-world scenarios like databases or real-time analytics often require pd-ssd or local SSDs to meet performance SLAs.

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.

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FAQ

Questions learners often ask

What does this PCA question test?

Ensure solution and operations reliability — This question tests Ensure solution and operations reliability — Read the scenario before looking for a memorised answer..

What is the correct answer to this question?

The correct answer is: The default node pool uses pd-standard disks, which have low IOPS. — The default node pool in GKE uses pd-standard (standard persistent disk) which provides lower IOPS compared to pd-ssd. For applications requiring high disk I/O performance, pd-standard disks become a bottleneck, causing high latency. Upgrading to pd-ssd or using local SSDs would resolve this issue.

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.

Are there clue words in this question I should notice?

Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.

What is the key concept behind this question?

Read the scenario before looking for a memorised answer.

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Last reviewed: Jun 30, 2026

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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.