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PROFESSIONAL-DATA-ENGINEER · Question #19

Your company's on-premises Apache Hadoop servers are approaching end-of-life, and IT has decided to migrate the cluster to Google Cloud Dataproc. A like-for- like migration of the cluster would requir

A is correct because Cloud Dataproc is natively integrated with Google Cloud Storage (GCS), which costs significantly less than Persistent Disk - GCS is object storage priced at a fraction of block storage rates. By storing all Hadoop data in GCS instead of on-node Persistent Dis

Submitted by olafpl· Mar 30, 2026Designing data processing systems

Question

Your company's on-premises Apache Hadoop servers are approaching end-of-life, and IT has decided to migrate the cluster to Google Cloud Dataproc. A like-for- like migration of the cluster would require 50 TB of Google Persistent Disk per node. The CIO is concerned about the cost of using that much block storage. You want to minimize the storage cost of the migration. What should you do?

Options

  • APut the data into Google Cloud Storage.
  • BUse preemptible virtual machines (VMs) for the Cloud Dataproc cluster.
  • CTune the Cloud Dataproc cluster so that there is just enough disk for all data.
  • DMigrate some of the cold data into Google Cloud Storage, and keep only the hot data in Persistent Disk.

Explanation

A is correct because Cloud Dataproc is natively integrated with Google Cloud Storage (GCS), which costs significantly less than Persistent Disk - GCS is object storage priced at a fraction of block storage rates. By storing all Hadoop data in GCS instead of on-node Persistent Disk, you achieve the same functionality at a much lower cost, and Dataproc's Cloud Storage connector handles HDFS-compatible access transparently.

B is wrong because preemptible VMs reduce compute costs, not storage costs - they don't address the 50 TB per node Persistent Disk concern at all.

C is wrong because tuning disk capacity is a marginal optimization; if the data genuinely requires 50 TB per node, you can't tune your way out of that need - you'd still be paying for expensive block storage.

D is wrong because it's a partial solution - splitting data between GCS (cold) and Persistent Disk (hot) still incurs high block storage costs for the hot tier. Option A eliminates Persistent Disk for data storage entirely, which is the maximum cost reduction.

Memory tip: Think of Dataproc as "HDFS replaced by GCS" - just as HDFS was the storage layer for on-prem Hadoop, GCS plays that role in the cloud, and object storage is always cheaper than block storage at scale.

Topics

#Cloud Dataproc#Google Cloud Storage#Cost Optimization#Data Migration

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