S3 Intelligent-Tiering
- What it is
- An Amazon S3 storage class that moves each object between access tiers automatically, based on how that object is actually used.
- The tiers it moves through
- Frequent Access → Infrequent Access after 30 days without access → Archive Instant Access after 90 days.
- Optional opt-in asynchronous tiers: Archive Access (90+ days) and Deep Archive Access (180+ days), which reintroduce retrieval time.
- Touch an object and it moves straight back to Frequent Access.
- The economics
- Small per-object monitoring and automation fee; no retrieval fees, so a wrong guess never produces a surprise bill.
- Objects under 128 KB are not monitored and stay in the Frequent tier — the fee would exceed the savings.
- When to use it
- Access patterns are unknown, changing, or unpredictable, and nobody wants to maintain lifecycle policies.
- Not to be confused with
- lifecycle policies — you write age-based rules. Intelligent-Tiering observes real access instead.
- Exam signal
- “Unknown or changing access patterns”, “optimize cost automatically” → Intelligent-Tiering.