Cloud Storage and Dataflow: How to Achieve a 15-Minute RPO with Pub/Sub?

PDE By islever Editorial Last updated Aug 31, 2026

Short answer

D 1. Use a dual-region Cloud Storage bucket with turbo replication enabled.

Question

You have designed an Apache Beam processing pipeline that reads from a Pub/Sub topic. The topic has a message retention duration of one day, and writes to a Cloud Storage bucket. You need to select a bucket location and processing strategy to prevent data loss in case of a regional outage with an RPO of 15 minutes. What should you do?

1. Use a dual-region Cloud Storage bucket.
1. Use a multi-regional Cloud Storage bucket.
1. Use a regional Cloud Storage bucket.
1. Use a dual-region Cloud Storage bucket with turbo replication enabled.
Correct Answer

Key Takeaways

This question tests whether you know that default dual-region replication is asynchronous and not sufficiently fast for a 15-minute RPO; the correct answer flags turbo replication as the feature that guarantees this RPO.

Learn how to configure a Cloud Storage bucket and Apache Beam pipeline to prevent data loss during a regional outage. Community consensus is that a dual-region bucket with turbo replication is required to meet a 15-minute RPO, combined with Pub/Sub seek-replay.

Common mistake: Selecting a plain dual-region bucket (option A) because dual-region sounds geo-redundant; however, without turbo replication, Cloud Storage can take hours or up to 12 hours to replicate data, failing the RPO requirement.

Expert Analysis

Why the Answer Is Correct

Option D is correct because a dual-region Cloud Storage bucket with turbo replication is explicitly designed to provide an RPO of 15 minutes for 100% of newly written objects. As one commenter noted, the official docs state that turbo replication ensures replication to both regions within 15 minutes regardless of object size.

A dual-region bucket without turbo replication (A) does not guarantee this RPO; its replication is eventual and can take up to 12 hours in the worst case. Therefore, only D satisfies the stated 15-minute RPO.

Additionally, the full strategy includes seeking the Pub/Sub subscription back in time and restarting the Dataflow job in a secondary region, which is essential for recovering acknowledged messages that may not have been fully written to the bucket yet.

Why the Other Options Are Wrong

Option A is wrong because it relies on a plain dual-region bucket without turbo replication, which cannot meet a 15-minute RPO. The replication lag could be hours, causing data loss in an outage.

Option B (multi-regional) may provide geo-redundancy but is not the specific recommended strategy for meeting a low RPO with Dataflow and Pub/Sub replay; it also lacks the turbo replication guarantee.

Option C (regional) stores data in a single region, so a regional outage would make the output unavailable and likely cause permanent data loss.

Community comments supporting A often mistake default dual-region replication for synchronous replication, but official documentation shows turbo replication is needed for the 15-minute RPO.

Community Comment Notes

Comment [1] (likes=8) outlines the full winning workflow: enable turbo replication, monitor with Cloud Monitoring, seek the subscription back 60 minutes, and start in a secondary region. This matches option D.

Comment [2] (likes=5) correctly explains that a plain dual-region bucket without turbo replication takes at least 1 hour to sync and has a 12-hour SLA for full replication, so it fails the RPO.

Comment [3] (likes=4) directly quotes the Cloud Storage documentation: turbo replication is designed to replicate 100% of newly written objects within 15 minutes.

Comments [5] and [6] argue that turbo makes the seek step unnecessary, but they ignore that seek-replay covers in-flight Dataflow data, not just the bucket replication; both mechanisms work together.

Official Reference

These links open the official vendor documentation in a new tab.

Exam Strategy

When you see "RPO of 15 minutes" in a Dataflow/Cloud Storage scenario, immediately look for the phrase "turbo replication" in the answer options. Also remember that a complete disaster recovery setup always includes a Pub/Sub seek-back step to replay acknowledged messages, so don't choose an answer that only discusses the bucket type.

Community Votes

82%

18%

82% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.

Discussion 9 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 9

datapassionate 👍 8 Answered D

D. 1. Use a dual-region Cloud Storage bucket with turbo replication enabled. 2. Monitor Dataflow metrics with Cloud Monitoring to determine when an outage occurs. 3. Seek the subscription back in time by 60 minutes to recover the acknowledged messages. 4. Start the Dataflow job in a secondary region. RPO of 15 minutes is guaranteed when turbo replication is used https://cloud.google.com/storage/docs/availability-durability
JyoGCP 👍 5 Answered D

Option D is correct. Not A, because dual-region bucket WITHOUT turbo replication takes atleast 1 hour to sync data between regions. SLA for 100% data sync is 12 hours as per google.
lipa31 👍 4 Answered D

https://cloud.google.com/storage/docs/availability-durability#turbo-replication says : "When enabled, turbo replication is designed to replicate 100% of newly written objects to both regions that constitute the dual-region within the recovery point objective of 15 minutes, regardless of object size." so seems D to me
raaad 👍 1 Answered A

- Low RPO: Dual-region buckets offer synchronous replication, ensuring data is immediately available in both regions, aligning with the 15-minute RPO. - Turbo Replication: enabling turbo replication can further reduce replication latency to near-real-time for even stricter RPO requirements. - Resilient Data Storage: Dual-region buckets ensure data availability even during regional outages, protecting processed data. - Fast Recovery: Reprocessing from the last 15 minutes of acknowledged messages minimizes data loss and downtime.
LP_PDE 👍 1 Answered D

Could be A or D. The choice between a 15-minute seek and a 60-minute seek depends on your specific requirements and priorities. If a very low RPO is critical, a 60-minute seek might be necessary to ensure data completeness.If minimizing cost and processing time is more important, a 15-minute seek might be sufficient, especially if you're confident in the reliability of Turbo Replication.

Show 4 more comments

m_a_p_s 👍 1 Answered A

An RPO of 15 minutes seemingly suggests using Turbo Replication. But here's the thing - why would you want to seek the subscription back in time by 60 minutes and run the Dataflow job? Thus, if turbo replication is enabled, steps 3 & 4 are completely redundant and unnecessary. Which is why option A is correct. This was a tricky one!
scaenruy 👍 1 Answered A

A. 1. Use a dual-region Cloud Storage bucket. 2. Monitor Dataflow metrics with Cloud Monitoring to determine when an outage occurs. 3. Seek the subscription back in time by 15 minutes to recover the acknowledged messages. 4. Start the Dataflow job in a secondary region.
shangning007 👍 1 Answered A

I don't like answer D. If we have turbo replication can ensure that change within 15min can be replicated, why do we still need to seek the subscription back in time by 60min?
SVGoogle89 👍 1

D https://cloud.google.com/storage/docs/availability-durability#cross-region-redundancy

Reader comments & corrections

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

← Back to PDE Study Guide