easyMultiple ChoiceObjective-mapped
PDE Practice Question: A data engineer needs to process a large dataset…
A data engineer needs to process a large dataset (500 TB) stored in Cloud Storage using Dataproc. The processing job requires reading the entire dataset and writing results back to Cloud Storage. The job is expected to run for 6 hours. Which configuration minimizes cost?
⚠ Common exam trap
Google Cloud often tests the misconception that local SSDs always improve performance for data processing jobs, but in Dataproc, when data resides in Cloud Storage, the bottleneck is network throughput, not local disk speed, making SSDs an unnecessary cost.
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
✓
Use a cluster with a mix of standard and preemptible VMs.
Preemptible VMs cost about 80% less than standard VMs, and mixing them with standard VMs provides fault tolerance for the job's 6-hour duration. Since the job reads and writes to Cloud Storage (not local HDFS), local SSDs are unnecessary, and a single-node cluster would lack the parallelism needed to process 500 TB efficiently within 6 hours. Using a mix of standard (for critical master/worker nodes) and preemptible VMs (for worker nodes) minimizes cost while ensuring job completion.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Use a single-node cluster with standard VMs.
Why it's wrong here
A single node may not have enough resources and is not cost-efficient for 500 TB.
- ✗
Use a cluster with local SSDs for faster I/O.
Why it's wrong here
Local SSDs are not necessary when reading from Cloud Storage.
- ✓
Use a cluster with a mix of standard and preemptible VMs.
Why this is correct
Preemptible VMs reduce cost significantly while providing sufficient compute.
- ✗
Use a cluster with n1-highmem-32 instances and 1000 cores.
Why it's wrong here
High-memory instances are more expensive and may be overkill.
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This PDE 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 PDE exam.