Task Statement 4.1: Design cost-optimized storage solutions.
📘AWS Certified Solutions Architect – (SAA-C03)
1. What is Storage Tiering?
Storage tiering is a strategy to store data in different types of storage based on how often it’s accessed and its importance.
- Hot data: Frequently accessed → faster storage.
- Cold data: Rarely accessed → cheaper, slower storage.
- Archived data: Rarely or almost never accessed → lowest-cost storage.
The main goal is cost optimization: you pay less for storage that you don’t access often.
2. Why Storage Tiering Matters in AWS
AWS provides multiple storage options, each with different costs and access speeds. By using tiering:
- You save money by moving inactive data to cheaper storage.
- You improve performance for critical data stored in faster storage.
- You meet compliance and retention requirements with archival tiers.
AWS has built-in options for tiering in object storage, block storage, and file storage.
3. Storage Tiering for Object Storage (S3)
Amazon S3 (Simple Storage Service) is the main service for object storage. It has different storage classes to implement tiering:
S3 Storage Classes
| Storage Class | Access Frequency | Use Case | Cost |
|---|---|---|---|
| S3 Standard | Frequent access | Active files, workloads | Highest |
| S3 Standard-IA (Infrequent Access) | Less frequent access | Backup, older files | Cheaper than Standard |
| S3 One Zone-IA | Less frequent access, single AZ | Cost-sensitive infrequent files | Cheaper but less resilient |
| S3 Glacier Instant Retrieval | Rare access, fast retrieval | Archival, but sometimes needed | Very cheap |
| S3 Glacier Flexible Retrieval | Rare access, slower retrieval | Long-term archiving | Cheapest |
| S3 Glacier Deep Archive | Very rare access | Compliance, long-term retention | Lowest cost |
How Tiering Works in S3
- Data starts in S3 Standard if frequently accessed.
- After a period of inactivity (e.g., 30 days), it moves to Standard-IA.
- Older or archival data moves to Glacier or Deep Archive.
AWS can automate this with S3 Lifecycle Policies.
Example: A company keeps daily logs in Standard. After 30 days, logs move to Standard-IA. After a year, logs move to Glacier Deep Archive. This reduces cost while still keeping the data accessible if needed.
4. Storage Tiering for Block Storage (EBS)
Amazon EBS (Elastic Block Store) provides block-level storage for EC2 instances. EBS uses tiering in volume types:
| Volume Type | Performance | Use Case | Cost |
|---|---|---|---|
| General Purpose SSD (gp3/gp2) | Balanced | OS disks, apps | Medium |
| Provisioned IOPS SSD (io2/io2 Block Express) | High | Databases, critical apps | High |
| Throughput Optimized HDD (st1) | Moderate | Big data, logs | Cheaper |
| Cold HDD (sc1) | Low | Infrequent access | Cheapest |
Example:
- Database runs on io2 for high performance.
- Old log files stored on sc1 to reduce cost.
5. Storage Tiering for File Storage (EFS)
Amazon EFS (Elastic File System) supports automatic tiering between:
- EFS Standard: Frequently accessed files.
- EFS Infrequent Access (EFS IA): Files not accessed often → cheaper storage.
EFS automatically moves files from Standard → IA after 30 days of inactivity.
6. Automation in AWS Storage Tiering
AWS provides automation to move data across tiers:
- S3 Lifecycle Policies – for moving objects between S3 classes.
- EFS Lifecycle Management – for moving files between Standard → IA.
- EBS Snapshots – older snapshots can be stored in S3 Glacier to save costs.
Automation ensures:
- Less manual work
- Cost savings without losing access to data
- Compliance with retention policies
7. Key Exam Points to Remember
- Cold tiering is about moving data to lower-cost storage based on usage.
- S3 lifecycle policies are the main way to implement object storage tiering.
- EFS and EBS have tiered options for infrequently accessed data.
- Tiering helps save costs while retaining data availability when needed.
- Deep archival tiers (Glacier/Deep Archive) have slower retrieval times.
AWS exam questions may ask you: “Which storage class or volume type is most cost-efficient for rarely accessed data?”
✅ Summary:
Storage tiering in AWS is all about matching storage type to access frequency. Hot, frequently used data stays in fast, expensive storage. Cold, rarely accessed data moves to cheaper storage. AWS automates this with S3 lifecycle policies, EFS IA, and EBS cold volumes, which helps optimize costs while ensuring the data is available when needed.
