What's changed: In-scope coverage: added compute placement (Elastic Beanstalk/Outposts/VMware Cloud on AWS/Wavelength/Serverless Application Repository/ECS Anywhere/EKS Anywhere/EKS Distro), cost visibility (Cost and Usage Report/Compute Optimizer/License Manager), and management/governance (CloudFormation/Service Catalog/Control Tower/Systems Manager/CloudWatch/X-Ray/Managed Grafana/Managed Service for Prometheus/Health Dashboard/Well-Architected Tool/Management Console) across sections
4.2Storage Cost Optimization
Understand S3 storage classes (Standard / Standard-IA / Glacier), lifecycle policies, and optimizing cost by choosing the right storage.
Storage cost is optimized by choosing a class based on access frequency. S3 offers storage classes for different needs.
4.2.1S3 storage classes
- S3 Standard: for frequently accessed data; higher storage cost, but no retrieval fee and fast access.
- S3 Standard-IA / One Zone-IA: infrequent access, cheaper storage (retrieval fee); One Zone-IA is cheaper in a single AZ with less redundancy.
- S3 Glacier (Instant/Flexible/Deep Archive): cheapest for archival; retrieval takes time (Deep Archive is cheapest/slowest).
- S3 Intelligent-Tiering: auto-moves objects to the optimal class by access frequency when patterns are unknown.
- Lifecycle policies: auto-transition to cheaper classes or delete over time.
Storage cost is optimized by matching the class to access frequency. Frequently read data → Standard (no retrieval fee); rarely used but retained → Standard-IA (cheap storage); long-term archives → cheapest Glacier tiers (retrieval takes time). New data on Standard, aging data to cheaper tiers—automate this with lifecycle policies (e.g., IA after 30 days, Glacier after 90, delete after a year). When access is unpredictable, Intelligent-Tiering monitors frequency and optimizes automatically. Cost trades off against retrieval speed/fees—work backward from how fast and how often you retrieve.
| Class | Access frequency | Trait |
|---|---|---|
| S3 Standard | Frequent | No retrieval fee, higher storage cost |
| Standard-IA | Infrequent | Cheap storage, retrieval fee |
| Glacier family | Archive | Cheapest, retrieval takes time |
| Intelligent-Tiering | Unknown/variable | Auto-optimizes class |
Scenario: storing logs and backups. Keep recent logs on Standard for search, move to Standard-IA after 30 days, archive audit data to Glacier after 90 days (rare retrieval is fine), and auto-delete after a year—all automated via lifecycle policies. For datasets with unpredictable access, let Intelligent-Tiering handle it. Choose tiers by retrieval speed/frequency requirements.
Watch the mix-ups: (1) frequent = Standard / infrequent = Standard-IA / archive = Glacier. (2) IA/Glacier have cheap storage but retrieval fees/time—frequent retrieval gets expensive. (3) Unknown access → Intelligent-Tiering. (4) Automate transitions with lifecycle policies. Note One Zone-IA has lower redundancy.
Q. Standard-IA vs Glacier? IA for occasional immediate retrieval; Glacier for long-term storage where rare/slow retrieval is fine. Q. When Intelligent-Tiering? When access is unpredictable/variable—it optimizes automatically. Q. Auto-move to cheaper tiers? Define day-based transitions/deletions with lifecycle policies.
Common: frequent = Standard, infrequent = Standard-IA, archive = Glacier, unknown/variable = Intelligent-Tiering, and lifecycle policies for auto-tiering. IA/Glacier incur retrieval fees/time.
4.2.2Section summary
- Standard (frequent) / Standard-IA (infrequent) / Glacier (archive) / Intelligent-Tiering (unknown)
- Use lifecycle policies to auto-transition/delete to cheaper tiers by age
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Quick check
(just a quick review)Q1. Which S3 class best fits low-cost long-term archival of rarely accessed data?
Q2. Which auto-transitions or deletes S3 objects over time to cheaper classes?
Q3. Which S3 feature auto-moves data with unpredictable access to the optimal class?
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