AWS Storage and Compute
Storage questions give you an access pattern and ask for the cheapest class that meets it. Compute questions give you a workload shape and ask for the cheapest purchasing model. Both are lookup problems once the tables are memorized.
AWS Storage and Compute · firsttry.app/cheatsheets/aws-storage-and-compute · original reference written from published exam objectives. Not affiliated with any certification body.
S3 storage classes
| Class | Access pattern | Retrieval | Minimum duration |
|---|---|---|---|
| Standard | Frequent | Milliseconds | None |
| Intelligent-Tiering | Unknown or changing | Milliseconds | None |
| Standard-IA | Infrequent, rapid when needed | Milliseconds | 30 days |
| One Zone-IA | Infrequent, reproducible data | Milliseconds | 30 days |
| Glacier Instant Retrieval | Archive, needs instant access | Milliseconds | 90 days |
| Glacier Flexible Retrieval | Archive, hours acceptable | Minutes to hours | 90 days |
| Glacier Deep Archive | Long-term retention | Up to 12 hours | 180 days |
EBS volume types
| Type | Media | Best for |
|---|---|---|
| gp3 | SSD | General purpose. Baseline throughput, independent of size |
| gp2 | SSD | General purpose, IOPS scales with size. Superseded by gp3 |
| io2 / io2 Block Express | SSD | High IOPS, durability sensitive databases |
| st1 | HDD | Throughput workloads, big sequential reads |
| sc1 | HDD | Coldest, lowest cost, infrequent access |
EC2 purchasing options
| Option | Discount | Suits |
|---|---|---|
| On-Demand | None | Short, unpredictable workloads |
| Savings Plans | Up to 72% | Committed spend, flexible across instance types |
| Reserved Instances | Up to 72% | Steady state, one or three year commitment |
| Spot Instances | Up to 90% | Interruptible work. Two-minute termination notice |
| Dedicated Hosts | Varies | Licensing tied to physical sockets, compliance |
| Dedicated Instances | Varies | Isolated hardware without host visibility |
Storage service selection
| Need | Service |
|---|---|
| Object storage over HTTP | S3 |
| Block storage for one EC2 instance | EBS |
| Shared POSIX filesystem for Linux | EFS |
| Shared SMB filesystem for Windows | FSx for Windows File Server |
| Temporary storage tied to instance life | Instance store |
| Hybrid on-premises to cloud storage | Storage Gateway |
| Petabyte-scale physical transfer | Snowball family |
Try it here
Three verified practice questions on this material. Answer one, and see the official page behind the answer.
4-1Billing, Pricing, and Support
How much warning does an EC2 Spot Instance get before it is interrupted?
2-1Design Resilient Architectures
A retail site caches product prices in ElastiCache. Prices are updated frequently, and users see stale prices for minutes after a change. Which caching strategy fixes this?
Monitoring, Logging, Analysis, Remediation, and Performance Optimization
For how long does CloudWatch preserve the history of an alarm?
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