What is the difference between S3 Standard, S3 Infrequent Access, and S3 Glacier?

AWS S3 offers storage classes with different cost/access tradeoffs:

• Standard: High durability, low latency, high throughput. For frequently accessed data.
• Standard-IA (Infrequent Access): Same latency as Standard but cheaper storage cost. Higher per-retrieval cost. Use for data accessed less than once a month.
• Glacier Instant Retrieval: For archive data accessed a few times per year. Millisecond retrieval.
• Glacier Deep Archive: Lowest cost. Retrieval takes 12 hours. Use for compliance/regulatory long-term retention.

Use S3 Lifecycle Policies to automatically transition objects between classes based on age.