How to minimize costs for immutable BigQuery backups?
Short answer
D 1. Perform a BigQuery export to a Cloud Storage bucket with archive storage class.
Question
Key Takeaways
This question tests knowledge of Cloud Storage classes for cost optimization and the use of Bucket Locks for data immutability, distinguishing them from BigQuery native features like snapshots.
To minimize costs for rarely accessed BigQuery data requiring immutability, export the data to a Cloud Storage bucket using the Archive storage class and configure a Bucket Lock. The community consensus confirms this is the most cost-effective method to meet the 3-year retention requirement.
Common mistake: Choosing BigQuery snapshots (Option B) is a common error because, while they preserve data, they are more expensive than Cloud Storage Archive class for long-term cold storage and lack specific WORM compliance features.
Expert Analysis
Why the Answer Is Correct
Option D is the correct choice because exporting to Cloud Storage with the Archive storage class provides the lowest cost for data accessed less than once a year. To meet the immutability requirement for 3 years, a Bucket Lock or retention policy must be applied to the bucket, ensuring the data cannot be modified or deleted during that period.
Why the Other Options Are Wrong
BigQuery table clones (Option A) and snapshots (Option B) keep the data within BigQuery, which is more expensive than Cloud Storage Archive. While snapshots are useful for point-in-time recovery, they do not inherently provide the strict immutability (WORM) guarantees required for compliance-heavy backups like a Bucket Lock does.
Community Comment Notes
Community members strongly support Option D, specifically noting the necessity of using a "bucket lock with retention policy" to satisfy the 3-year immutability constraint. The comments indicate that the combination of exporting to cold storage and applying a lock is the standard solution for this scenario.
Official Reference
- https://cloud.google.com/storage/docs/bucket-lock
- https://cloud.google.com/storage/docs/storage-classes
- https://cloud.google.com/bigquery/docs/exporting-data
These links open the official vendor documentation in a new tab.
Exam Strategy
When a question requires data to be immutable for a specific duration, look for Cloud Storage Bucket Lock or retention policies rather than database snapshots. Always prioritize the Archive storage class for data accessed once a year or less to ensure the lowest storage costs.
Community Votes
100% of anonymous learners picked answer D. Votes are pick records left by other test-takers — they are not the verified answer.
Discussion 6 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 6
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GCP001 👍 2D. For data keeping till last 3 years, use bucket lock with rentention policy
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fitri001 👍 2 Answered DFor data keeping till last 3 years, use bucket lock with rentention policy
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raaad 👍 5 Answered DStraight Forward
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Matt_108 👍 2 Answered DOption D, clearly
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JyoGCP 👍 1 Answered DOption D
Show 1 more comment
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hanoverquay 👍 1 Answered Dvoted D
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