S3 storage classes (Standard, IA, Glacier) in AWS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding S3 Storage Classes Cost Behavior

You have three files stored in Amazon S3 using different storage classes: Standard, Infrequent Access (IA), and Glacier. Which storage class will incur the highest cost when you retrieve the files frequently?

A Glacier storage class

B Standard storage class

C Infrequent Access (IA) storage class

D All have the same cost for frequent retrieval

💡 Hint

Think about which storage classes charge extra for data retrieval.

Standard class is designed for frequent access with no retrieval fees. IA charges lower storage but adds retrieval fees. Glacier has the lowest storage cost but high retrieval fees and delays, making it the most costly for frequent access.

❓ service_behavior

intermediate

S3 Glacier Retrieval Time Behavior

You request to retrieve an object stored in S3 Glacier. Which statement best describes the retrieval time?

A The object is deleted after retrieval request.

B The object is available immediately after the request.

C The object retrieval takes minutes to hours depending on retrieval option.

D The object retrieval time is the same as Standard storage class.

💡 Hint

Glacier is designed for long-term storage with delayed access.

Glacier retrievals can take from minutes to hours depending on the retrieval tier chosen (Expedited, Standard, or Bulk). It is not immediate like Standard storage.

❓ Architecture

advanced

Designing Cost-Effective S3 Storage for Mixed Access Patterns

You manage a dataset where 80% of files are accessed frequently and 20% are rarely accessed. Which S3 storage class combination is best to minimize cost while maintaining performance?

A Store all files in Standard storage class.

B Store frequently accessed files in Standard and rarely accessed files in Infrequent Access (IA).

C Store all files in Glacier storage class.

D Store frequently accessed files in IA and rarely accessed files in Glacier.

💡 Hint

Consider balancing storage cost and retrieval cost based on access frequency.

Standard class is best for frequent access. IA offers lower storage cost but retrieval fees, suitable for rarely accessed files. Glacier is too slow for frequent access and not cost-effective for 20% rarely accessed files if retrieval is needed often.

❓ security

advanced

Securing S3 Glacier Data with Encryption and Access Controls

Which of the following is the best practice to secure data stored in S3 Glacier?

A Disable encryption and rely on bucket policies only.

B Use client-side encryption only and allow all users to retrieve data.

C Store data without encryption but enable public read access.

D Use server-side encryption with AWS KMS and restrict access with IAM policies.

💡 Hint

Think about encryption and access control layers.

Best practice is to use server-side encryption with AWS KMS for strong encryption and control access with IAM policies. Public read or no encryption exposes data to risks.

✅ Best Practice

expert

Optimizing Lifecycle Policies for S3 Storage Classes

You want to automate moving objects from Standard to IA after 30 days, then to Glacier after 90 days, and finally delete after 365 days. Which lifecycle policy configuration correctly implements this?

AWS

LifecycleConfiguration:
  Rules:
    - ID: MoveToIA
      Status: Enabled
      Filter: {}
      Transitions:
        - Days: 30
          StorageClass: STANDARD_IA
        - Days: 90
          StorageClass: GLACIER
      Expiration:
        Days: 365

A The policy moves objects to IA after 30 days, then Glacier after 90 days, and deletes after 365 days.

B The policy moves objects to IA after 30 days and deletes after 90 days, skipping Glacier.

C The policy deletes objects after 30 days without any transitions.

D The policy moves objects directly to Glacier after 30 days and deletes after 365 days.

💡 Hint

Check the order and timing of transitions and expiration.

The lifecycle policy transitions objects first to IA at 30 days, then to Glacier at 90 days, and finally deletes them at 365 days, matching the requirement.