Task Statement 4.1: Design cost-optimized storage solutions.
📘AWS Certified Solutions Architect – (SAA-C03)
Overview
Block storage is a type of storage where data is stored in fixed-size blocks. Each block has its own address, and the operating system can read/write data directly at the block level. Block storage is ideal for:
- Databases
- Virtual machines
- Applications requiring high performance or low latency
- Systems that need fast, consistent I/O (Input/Output) operations
In AWS, Amazon Elastic Block Store (EBS) is the main service for block storage.
EBS Volume Types
AWS EBS offers different volume types optimized for performance and cost. They are mainly categorized as:
- SSD (Solid State Drive) Volumes – Fast, low-latency storage.
- HDD (Hard Disk Drive) Volumes – Cheaper, higher-latency storage for large sequential workloads.
Let’s dive into each.
1. SSD (Solid State Drive) Volume Types
Use Case: High-performance workloads where speed and low latency are critical.
AWS provides two main SSD types:
a) General Purpose SSD (gp3, gp2)
- gp3 is the newer version of gp2, better performance at a lower cost.
- Performance: Up to 16,000 IOPS and 1,000 MB/s throughput.
- Cost: Moderate, suitable for most workloads.
- Use Case Example in IT:
- Databases like MySQL or PostgreSQL
- Boot volumes for EC2 instances
- Web servers needing consistent response time
Exam Tip: Know that gp3 is cost-optimized compared to gp2 and allows you to provision extra IOPS and throughput independently of size.
b) Provisioned IOPS SSD (io2, io2 Block Express)
- Performance: Extremely high, up to 256,000 IOPS with Block Express.
- Durability: Designed for mission-critical applications (99.999% durability).
- Use Case Example in IT:
- High-performance NoSQL databases like Cassandra or MongoDB
- Enterprise-grade Oracle or SQL Server databases
- Applications needing extremely low latency (<1 ms)
Exam Tip: For cost-optimization, only use io2 when your application truly requires high IOPS.
2. HDD (Hard Disk Drive) Volume Types
Use Case: Large, sequential workloads where cost is more important than speed.
AWS provides two main HDD types:
a) Throughput Optimized HDD (st1)
- Performance: Designed for large, sequential workloads, like reading/writing big files.
- Throughput: Up to 500 MB/s per volume.
- Use Case Example in IT:
- Data warehouses
- Log processing
- Streaming large datasets
Exam Tip: st1 is not suitable for boot volumes or random I/O workloads like databases.
b) Cold HDD (sc1)
- Performance: Lowest-cost, for rarely accessed data.
- Throughput: Lower than st1, up to 250 MB/s.
- Use Case Example in IT:
- Backup storage
- Archival of historical logs
- Large cold datasets
Exam Tip: sc1 is the cheapest EBS option, ideal for cost-saving strategies in long-term storage.
Comparison Table for Easy Exam Reference
| Volume Type | Storage Type | Use Case | Max IOPS | Throughput | Cost Level |
|---|---|---|---|---|---|
| gp3 | SSD | General purpose workloads | 16,000 | 1,000 MB/s | Moderate |
| io2/io2 Block Exp | SSD | High-performance databases | 256,000 | 4,000 MB/s | High |
| st1 | HDD | Big sequential data | 500 | 500 MB/s | Low |
| sc1 | HDD | Cold/archival data | 250 | 250 MB/s | Lowest |
Key Exam Points to Remember
- SSD = high performance, low latency. HDD = lower cost, sequential workloads.
- gp3 is the preferred general-purpose SSD for cost-optimization.
- Use io2/io2 Block Express only for mission-critical, high IOPS workloads.
- st1 = low-cost, frequently accessed large files. sc1 = cheapest, infrequently accessed cold data.
- Boot volumes generally use SSD (gp3).
- HDD volumes are optimized for throughput, not random I/O.
✅ Summary for the Exam:
- If your priority is speed → choose SSD (gp3 or io2)
- If your priority is cost and large sequential reads/writes → choose HDD (st1 or sc1)
- Always consider cost vs. performance: pick the lowest-cost volume that meets your workload requirements.
