Data Engineering Cloud Data Storage Solutions 2 — Questions and Answers
Question 1: Which AWS storage class is most cost-effective for archival data accessed less than once a year with retrieval times of hours?
- S3 Standard
- S3 Glacier Deep Archive (Correct answer)
- S3 Intelligent-Tiering
- S3 Standard-IA
Correct answer: S3 Glacier Deep Archive
S3 Glacier Deep Archive offers the lowest storage cost for rarely accessed long-term archives.
Question 2: What is the primary benefit of object storage over block storage for a data lake?
- Lower latency for random writes
- Massive scalability with rich metadata (Correct answer)
- Native file-system semantics
- Built-in transactional locking
Correct answer: Massive scalability with rich metadata
Object storage scales to virtually unlimited capacity and attaches metadata to each object, ideal for data lakes.
Question 3: In Google Cloud Storage, which feature automatically transitions objects between storage classes based on age?
- Object Versioning
- Lifecycle Management (Correct answer)
- Bucket Lock
- Requester Pays
Correct answer: Lifecycle Management
Lifecycle Management applies rules to move or delete objects as they age, optimizing cost.
Question 4: Which storage option is best suited for a high-throughput streaming workload requiring low-latency appends?
- Cold object storage
- A managed message/log store like Kafka or Kinesis (Correct answer)
- Glacier archive
- Read replica of a relational DB
Correct answer: A managed message/log store like Kafka or Kinesis
Log-based streaming stores are designed for high-throughput, low-latency append operations.
Question 5: What does 'eventual consistency' mean in a distributed cloud object store?
- Reads always return the latest write immediately
- Updates propagate over time and reads may briefly return stale data (Correct answer)
- Writes are rejected until all nodes confirm
- Data is never consistent across regions
Correct answer: Updates propagate over time and reads may briefly return stale data
Eventual consistency means replicas converge to the latest value after a propagation delay.
Question 6: Which factor most directly increases the cost of querying data stored in S3 via Amazon Athena?
- Number of buckets
- Amount of data scanned per query (Correct answer)
- Number of IAM users
- Region of the bucket
Correct answer: Amount of data scanned per query
Athena charges based on the volume of data scanned, so partitioning and columnar formats reduce cost.
Question 7: What is the main advantage of using a columnar format like Parquet in cloud storage?
- Faster row-by-row inserts
- Reduced scan size and better compression for analytics (Correct answer)
- Simpler human readability
- Native support for binary blobs only
Correct answer: Reduced scan size and better compression for analytics
Parquet stores data by column, enabling column pruning and high compression for analytical queries.
Data Engineering Cloud Data Storage Solutions 2
Which AWS storage class is most cost-effective for archival data accessed less than once a year with retrieval times of hours?