Exam Professional Data Engineer topic 1 question 249 discussion

https://cloud.google.com/storage/docs/autoclass

- Autoclass automatically moves objects between storage classes without impacting performance or availability, nor incurring retrieval costs. - It continuously optimizes storage costs based on access patterns without the need to set specific lifecycle management policies.

From the documentation https://cloud.google.com/storage/docs/autoclass

the question clearly specifies there should not be any retrieval charges. so enabling autoclass is not recommended because we have to pay one time fees while retrieving the data. and usually soft delete is enable.

Why B is the best choice: Cost Optimization: This option leverages Cloud Storage's different storage classes to significantly reduce costs for storing older data. Nearline, coldline, and archive storage classes are progressively cheaper than the standard storage class, with trade-offs in availability and retrieval times. Meets Requirements: Old data deletion: You can manually delete old data whenever needed, fulfilling the first requirement. No predefined access pattern: The policy automatically transitions data to cheaper storage classes based on age, regardless of access patterns. Instant availability: Nearline storage provides immediate access to data, meeting the third requirement. No retrieval charges: While there are retrieval charges for coldline and archive storage, nearline storage has no retrieval fees, satisfying the fourth requirement.

For sure A, read the documentation

autoclass is the correct way to handle all business cases

Create an Object Lifecycle Management policy to modify the storage class for data older than 30 days to nearline, 90 days to coldline, and 365 days to archive storage class. Delete old data as needed.