Professional Data EngineerBuilding and operationalizing data processing systemsMedium

A financial institution needs to store immutable audit logs for regulatory compliance. These logs are written once and rarely accessed after initial ingestion, but must be retained for 7 years. Cost optimization for storage is a critical factor, as the volume is expected to grow into petabytes. Which Cloud Storage class is most appropriate for this use case?

  1. AArchive
  2. BNearline
  3. CStandard
  4. DColdline
Show answer & explanation

Correct answer: A. Archive

Archive storage is the most cost-effective solution for data that is rarely accessed (less than once a year) and needs to be retained for long periods, making it ideal for immutable audit logs with a 7-year retention requirement.

Why the other options are wrong

  • B. Nearline storage is for data accessed less than once a month, still more costly than needed for 7-year retention with rare access.
  • C. Standard storage is for frequently accessed data and would be too expensive for rarely accessed audit logs.
  • D. Coldline storage is for data accessed less than once a quarter, better than Nearline but still not as cost-optimized as Archive for very infrequent access.

Cloud Storage Archive Class

The lowest-cost Cloud Storage class designed for long-term data archiving, backup, and disaster recovery. It offers very low storage costs but has higher data retrieval costs and a minimum storage duration.

  • Lowest storage cost per GB
  • Higher data retrieval costs and retrieval time
  • Minimum storage duration of 365 days
  • Ideal for data accessed less than once a year

Memory trick: Storage tiers: Hot to cold, cost to access.

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