What are the S3 storage classes, and how do you pick between them?
AWS · Basic level
Answer
S3 storage classes balance cost, durability, access frequency, and retrieval time. I use Standard for hot data, Intelligent-Tiering when access is uncertain, IA for infrequent access, and Glacier classes for archive and compliance retention.
Technical explanation
Retrieval fees and minimum storage duration can erase savings if objects are transitioned too aggressively.
S3 security should start with Block Public Access, least-privilege IAM/bucket policies, encryption, ownership controls, and CloudTrail or S3 data-event visibility for sensitive buckets.
Cost management depends on lifecycle policies, storage classes, version retention, object size, retrieval fees, and access patterns.
Operationally, validate bucket policies, KMS permissions, lifecycle effects, and restore behavior before applying broad production changes.
Hands-on example
1. Create a non-production bucket with Block Public Access, bucket owner enforced object ownership, default encryption, and scoped IAM access.
2. Add a policy control relevant to the question, such as deny non-TLS, require SSE-KMS, or restrict access to a VPC endpoint.
3. Enable versioning or lifecycle where relevant, upload test objects, and verify transitions, deletes, restores, and access-denied behavior.
4. Review Access Analyzer, Config, CloudTrail, and Storage Lens before applying the pattern to production.
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