Optimizing Data Transfer for ETL with Cellular Connections

PCA By islever Editorial Last updated

Designing network, storage, and compute resources.

Short answer

D Directly transfer files to a different Google Cloud Regional Storage bucket location in US, EU, and Asia using Google APIs over HTTP(S) to minimize latency and maximize throughput for the ETL process.

Question

To speed up data retrieval, more vehicles will be upgraded to cellular connections and be able to transmit data to the ETL process. The current FTP process is error-prone and restarts the data transfer from the start of the file when connections fail, which happens often. You want to improve the reliability of the solution and minimize data transfer time on the cellular connections.
What should you do?
  1. Use one Google Container Engine cluster of FTP servers. Save the data to a Multi-Regional bucket. Run the ETL process using data in the bucket
  2. Use multiple Google Container Engine clusters running FTP servers located in different regions. Save the data to Multi-Regional buckets in US, EU, and Asia. Run the ETL process using the data in the bucket
  3. Directly transfer the files to different Google Cloud Multi-Regional Storage bucket locations in US, EU, and Asia using Google APIs over HTTP(S). Run the ETL process using the data in the bucket
  4. Directly transfer the files to a different Google Cloud Regional Storage bucket location in US, EU, and Asia using Google APIs over HTTP(S). Run the ETL process to retrieve the data from each Regional bucket Correct Answer

Key Takeaways

The core trap is confusing content serving (where Multi-Regional excels) with data ingestion/ETL (where Regional provides better performance characteristics).

This question evaluates the best storage location strategy to minimize latency and maximize reliability for cellular data uploads destined for an ETL process. It establishes that Regional Storage is superior to Multi-Regional Storage for analytics ingestion due to lower latency and higher throughput.

Common mistake: Many learners select C (Multi-Regional) because they associate it with global availability and redundancy, failing to recognize that the scenario prioritizes transfer speed and reliability over immediate multi-region accessibility.

Expert Analysis

Why the Answer Is Correct

Option D is correct because the primary goal is to speed up data retrieval and minimize transfer time on cellular connections. According to Google Cloud documentation, Regional buckets offer significantly higher network bandwidth (up to 200 Gbps per region) compared to Multi-Regional buckets (50 Gbps per region). Furthermore, uploading to a single regional bucket reduces the overhead associated with replicating data across multiple geographic regions during the write phase, thereby minimizing latency and improving reliability for the initial upload.

Why the Other Options Are Wrong

Options A and B are incorrect because they propose using FTP servers hosted on Container Engine clusters. This introduces unnecessary complexity, management overhead, and potential points of failure compared to directly uploading to Cloud Storage via APIs. Option C is incorrect because while Multi-Regional buckets provide high availability, they incur higher latency during writes due to cross-region replication and have lower aggregate throughput limits per region, which contradicts the requirement to minimize data transfer time.

Community Comment Notes

Several community members correctly identified D by referencing official Google Cloud recommendations that distinguish between content serving and analytics use cases. As user n_nana noted, "multi-region is good for content serving and not analytics." User Kulwant85 highlighted the bandwidth difference, stating "Regional: 200 Gbps... Multi-regional: 50 Gbps," which supports the choice for faster transfers. User hems4all also emphasized that Multi-Regional is for external content serving, not internal ETL pipelines.

Official Reference

https://cloud.google.com/storage/docs/locations#location_recommendations

This link opens the official vendor documentation in a new tab.

Exam Strategy

Always align your storage choice with the specific workload pattern. For 'ingest and analyze' or ETL workflows where low-latency writes and high throughput are critical, prefer Regional buckets. Reserve Multi-Regional buckets for scenarios requiring low-latency reads from globally distributed users.

Frequently Asked Questions

Why not use Multi-Regional buckets for higher availability?

While Multi-Regional offers higher availability, it has lower write throughput limits and higher write latency due to cross-region replication. For ETL ingestion, speed and reliability of the initial upload are prioritized, making Regional buckets the better fit.

Is FTP ever recommended for cloud data ingestion?

No. Directly uploading to Cloud Storage via HTTPS APIs is more secure, scalable, and reliable than hosting custom FTP servers on VMs, which adds management overhead and potential single points of failure.

More PCA FAQ →

Community Votes

D
75%
C
25%

75% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 114 contributions

Compiled from public community threads and reader submissions, lightly edited for clarity. Handles and vote tallies are shown as recorded, and comments reflect the views of individual contributors.

From public community threads 30 of 114

  1. dabrat 👍 42
    c) Multi-Region Name Multi-Region Description asia Data centers in Asia eu Data centers in the European Union1 us Data centers in the United States multi-region is a large geographic area, such as the United States, that contains two or more geographic places.
  2. JJu 👍 18
    I think answer is C. Use a multi-region when you want to serve content to data consumers that are outside of the Google network and distributed across large geographic areas, or when you want the higher availability that comes with being geo-redundant.
  3. mister 👍 16
    D is correct. multi-regional is for external
  4. n_nana 👍 15 Answered D
    adding to other explanation, source https://cloud.google.com/storage/docs/locations#location_recommendations It's pretty clear that multi-region is good for content serving and not analytics. Only regional and dual regional buckets are good storage for analytics case which exist in the question
  5. Kulwant85 👍 11 Answered D
    https://cloud.google.com/storage/docs/locations#considerations Regional: 200 Gbps (per region, per project) Multi-regional: 50 Gbps (per region, per project)
Show 25 more comments
  1. tartar 👍 8
    C is ok
  2. hems4all 👍 7
    D is correct answer: We don't need Multi-Regional Storage buckets. Google recommends you use a multi-region when you want to serve content to data consumers that are outside of the Google network and distributed across large geographic areas, or when you want the higher availability that comes with being geo-redundant. This scenario is not the same as our scenario. While Multi-Regional Storage buckets are OK for this requirement, you are also paying extra for the additional features which are not needed. So, we might as well go with Regional buckets to keep costs minimal. Ref: https://cloud.google.com/storage/docs/locations#considerations
  3. amxexam 👍 7 Answered C
    1) We all know the issue is with the file sending mechanism. 2) Looking at the option direct bucket is better than FTP service hosted on VM. 3) Also, we will look for multi-regional so there is no latency for long-distance customers. Also, the company has 100 countries it is a multi-regional company. Hence C
  4. guid1984 👍 6
    IMHO the answer is C, because questions asks about two things "You want to improve the reliability of the solution and minimize data transfer time on the cellular connections." Reliability : - Since terram earth is a global company, i would build some geo redundancy by having multi-regional buckets. Minimize Cellular data transfer time: Please remeber its an upload to storage from devices (ingress) into GCP. Now with 20M devices globally, a multi-region GCS will have less latency in uploading data (due to edge locations/POP) and will minimize data transfer times.
  5. PeppaPig 👍 6
    D is correct using regional buckets The question mentioned one concerns around resumable upload, and for that you shouldn't use multi-region bucket as it might cause slow upload. see https://cloud.google.com/storage/docs/resumable-uploads#upload-performance
  6. surajkrishnamurthy 👍 6 Answered D
    D seems to be the correct answer Sending Data to all Multi Region Buckets >> Incurs more cost , More Latency Sending Data only to Regional Bucket >> Incurs less cost , Less Latency
  7. mudot 👍 6 Answered D
    I think the next question has answer to this, in the question :-)
  8. Jphix 👍 5
    Agreed. C. https://cloud.google.com/storage/docs/locations Regional = reduced latency for data consumers, such as in analytics pipelines (Exactly the scenario here) Multi-Regional = for when data consumer are outside of the Google network and distributed across large geographic areas. No indication that that the data consumers themselves are distributed across a large geographic area, just in two different spots in the US. The business requirements state that they want to "Expand beyond a single data center to decrease latency to the American Midwest and East Coast specifically."
  9. Google 👍 5
    I will go with D after reading this Use a region to help optimize latency and network bandwidth for data consumers, such as analytics pipelines, that are grouped in the same region. Use a dual-region when you want similar performance advantages as regions, but also want the higher availability that comes with being geo-redundant. Use a multi-region when you want to serve content to data consumers that are outside of the Google network and distributed across large geographic areas, or when you want the higher availability that comes with being geo-redundant.
  10. AD2AD4 👍 5
    Should we not emphasis on the FTP process error prone to fail. As if FTP is failing it would not be able to put data on GCS as well thus my thought process is getting inclined towards option B.
  11. BiddlyBdoyng 👍 5 Answered D
    D, multi-region increases latency
  12. babup 👍 4
    My Option is C: Key words: Want to improve the reliability of the solution and minimize data transfer time on the cellular connections. Ref document: Use a region to help optimize latency and network bandwidth for data consumers, such as analytics pipelines, that are grouped in the same region. Use a dual-region when you want similar performance advantages as regions, but also want the higher availability that comes with being geo-redundant. Use a multi-region when you want to serve content to data consumers that are outside of the Google network and distributed across large geographic areas, or when you want the higher availability that comes with being geo-redundant. Generally, you should store your data in a location that is convenient or contains the majority of the users of your data. Multi region bucket increase the availability and reduce the latency for upload.
  13. f0x 👍 4
    I'm going with D. Question states, "The current FTP process is error-prone and restarts the data transfer from the start of the file when connections fail, which happens often. You want to improve the reliability of the solution and minimize data transfer time on the cellular connections." https://cloud.google.com/storage/docs/locations "Use a region to help optimize latency and network bandwidth for data consumers, such as analytics pipelines, that are grouped in the same region." Plus, the next question reads, "... its telemetry data is stored in a Google Cloud Storage (GCS) regional bucket (US, Europe, or Asia)"
  14. Smart 👍 4
    I think C is more appropriate from performance perspective; while D is appropriate from cost perspective. For instance, setting up a Regional bucket on US East Coast will not 'dramatically' help uploads from West cost. In this scenario, not only there is a global presence but also a wide-spread distribution (across 100 countries). Additionally, we need to minimize transfer time. ("Use a multi-region when you want to serve content to data consumers that are outside of the Google network and distributed across large geographic areas, or when you want the higher availability that comes with being geo-redundant.")
  15. Toothpick 👍 4
    Everyone voting C are missing the point, you are not serving the data, merely ingesting it. For that , regional buckets provide better latency and bandwidth with lower costs. Multi-regions can be considered for redundancy in the case of regional failures , but it's costly and extremely unlikely for an entire region to go down , zonal replication is good enough in this case
  16. n_nana 👍 4
    Good point, in same source https://cloud.google.com/storage/docs/locations#location_recommendations It's pretty clear that multi-region is good for content serving and not analytics. Only regional and dual regional buckets are good storage for analytics case which exist in the question.
  17. nideesh 👍 4
    Container engine which has recyclable pods as FTP server is far fetched. Compute engine and containers should not be used for storage. GCS bucket is better as files can be uploaded from anywhere and is reliable and fast.
  18. HKim 👍 4
    I think D is better than C since regional storage buckets have lower latency for write. Multi-regional storage buckets have CDN integration for better read performance but that will not help here since we are writing.
  19. MeasService 👍 4
    D is realisting. Data in gsc will be only for staging. once moved it is not needed hence regional storage.
  20. KouShikyou 👍 4
    I thought correct answer is C. Is it possible to explain why D is selected?
  21. MamthaSJ 👍 4
    Answer is C
  22. parthkulkarni998 👍 3 Answered C
    Option C seems right here. Directly transferring the files to a different Google Cloud Regional Storage bucket location in US, EU, and Asia using Google APIs over HTTP(S), would not be an effective solution as it would not improve the reliability of the solution. Using Google Cloud Multi-Regional Storage, which stores the data in multiple locations, would be a more reliable solution.
  23. jespinosar 👍 3
    Multi-regional offers 2 main advantages: Resilience (availability) Low latency Even if we consider the US, if we use a regional bucket we'll face latency issues from cost to cost. Regional should only be used according to Google's doc in 2 cases 1) all your clients are in that region 2) Cost optimization So, C) is the right answer.
  24. mlantonis 👍 3
    Since the vehicles are spread all over the world and since later retrieving data is from centralized location, saving data to nearest regional bucket instead of mulit-regional bucket in a large geographic area and retrieve from there is a better solution to minimize data transfer on the cellular connections. D is the correct answer.
  25. AdityaGupta 👍 3
    Each question from case study should be read with entirety of case study presented. I think C is correct answer, because Multi-Regional Buckets will give you geo-redundant storage to server global customers which will also improve your reliability and minimize your data transfer time.

Reader comments & corrections

No reader corrections yet — spotted an error or have a note? Share it below.

Log in to comment, report an error, or add a note about this question.

Multi-Regional vs Regional Cloud Storage for Global Software Downloads

S-grade

Surviving a Zone Outage With SQL Server on GCP

S-grade

Fixing BigQuery connection errors from a Compute Engine VM

S-grade

Moving 75 TB into Cloud Storage with Google-recommended practices

S-grade

Practice All PCA Questions

Access 81 questions with complete answers and detailed explanations.

View Full PCA Practice Test →

← Back to PCA Study Guide