AWS Domain 4 – Cost Optimization Vocabulary

A comprehensive set of vocabulary flashcards covering the key cost-optimization terms, tools, and concepts for AWS Solutions Architect Associate Domain 4.

Object Storage

Flat-address storage architecture that keeps data as objects; massively scalable and durable (e.g., Amazon S3).

Block Storage

Raw, low-latency storage volumes that act like hard drives for EC2 (e.g., Amazon EBS).

File Storage

Shared, hierarchical file system accessible over a network (e.g., Amazon EFS, Amazon FSx).

Ephemeral Storage

Locally attached instance store that disappears when an EC2 instance stops, terminates, or fails.

Cost Allocation Tags

Key–value labels applied to resources so charges can be grouped and analyzed in Cost Explorer and CUR.

AWS Cost Explorer

Interactive console for visualizing, filtering, and forecasting AWS costs and usage at a high level.

AWS Cost and Usage Report (CUR)

The most granular billing file, delivered to S3, breaking charges down by hour, resource ID, and tags.

S3 Lifecycle Configuration

Bucket rules that automatically transition or delete objects after specified times to cut storage costs.

S3 Intelligent-Tiering

Storage class that automatically moves objects between frequent and infrequent tiers based on access.

AWS Snowball

Shippable appliance that transfers terabytes–petabytes of data into or out of AWS faster than the Internet.

Consolidated Billing

AWS Organizations feature that combines charges from multiple accounts into one bill for volume discounts.

Right-Sizing

Process of matching resource size, type, and performance to actual workload demand to avoid over-paying.

AWS Trusted Advisor

Service that scans your environment and offers real-time best-practice recommendations, including cost cuts.

Amazon Data Lifecycle Manager (DLM)

Automates creation, retention, and deletion of EBS snapshots and AMIs to control snapshot storage spend.

Requester Pays (S3)

Bucket option that shifts data-transfer charges to the downloader instead of the bucket owner.

AWS Backup

Centralized service for configuring, scheduling, and enforcing backup retention across many AWS resources.

Amazon CloudWatch

Monitoring service that collects metrics, logs, and alarms—crucial for spotting under-utilized resources.

AWS Budgets

Tool that lets you set cost or usage limits and receive alerts—or automated actions—when thresholds are hit.

AWS Organizations

Multi-account governance service providing centralized billing, policy control, and consolidated discounts.

Amazon CloudFront

Global CDN that caches content at edge locations, reducing latency and data-transfer-out charges from origins.

AWS DataSync

Agent-based service that accelerates secure online transfers between on-prem storage and AWS services.

AWS Storage Gateway

Hybrid appliance exposing on-prem file, tape, or volume interfaces backed by cloud storage like S3 or EFS.

AWS Direct Connect

Dedicated, private network link from a data center to AWS, offering consistent bandwidth and lower egress fees.

On-Demand Instances

EC2 pricing model with no commitment; billed per second or hour, most flexible and most expensive.

Reserved Instances (RIs)

Commitment to a specific instance family, region, and term (1–3 yrs) for up to 72 % cost reduction.

Savings Plans

Discount model that lowers prices across EC2, Fargate, and Lambda in exchange for a $/hour spend commitment.

Spot Instances

Deep-discount EC2 capacity that can be interrupted with a two-minute warning; ideal for fault-tolerant jobs.

Elasticity

Capability to automatically acquire and release resources so you pay only for what you use.

Elastic Load Balancer (ELB)

Managed service that distributes incoming traffic across multiple compute targets to improve availability.

AWS Outposts

Fully managed racks that extend AWS infrastructure and services into on-prem data centers for hybrid needs.

Horizontal Scaling

Adding more smaller instances (scaling out) to handle load; often cheaper and more resilient.

Vertical Scaling

Increasing CPU/RAM on a single instance (scaling up); may require downtime and higher per-unit cost.

Auto Scaling

Service that automatically adjusts EC2 (or other) capacity based on metrics like CPU or ALB request count.

Compute-Optimized Instances

C-family EC2 designed for CPU-intensive tasks such as batch processing or high-performance web servers.

Memory-Optimized Instances

R/X/Z-family EC2 designed for in-memory databases, real-time big-data analytics, or high-memory workloads.

General-Purpose Instances

M/T-family EC2 offering balanced compute, memory, and networking for diverse workloads.

Relational Database

Structured, table-based data store enforcing a schema and ACID transactions (e.g., Amazon RDS).

NoSQL Database

Schema-less, horizontally scalable data store for key-value, document, or graph models (e.g., DynamoDB).

Read Replica

Read-only copy of a database instance that offloads read traffic, enabling horizontal read scaling.

Point-in-Time Recovery (PITR)

Ability to restore a database to any second within its backup retention window.

Aurora Serverless

On-demand, auto-scaling Aurora cluster that starts, stops, and adjusts capacity automatically; pay per usage.

Amazon DynamoDB

Fully managed, serverless key-value NoSQL database that delivers single-digit-millisecond performance at scale.

Amazon ElastiCache

Managed in-memory cache (Redis or Memcached) used to offload frequent reads and speed up applications.

Polyglot Persistence

Architectural approach of using multiple data stores (RDS, S3, DynamoDB, etc.) each for its ideal workload.

Site-to-Site VPN

IPsec tunnel over the public Internet connecting on-prem networks to a VPC; quickest and cheapest hybrid link.

VPC Peering

One-to-one private connection that routes traffic between two VPCs without gateways or NAT devices.

AWS Transit Gateway

Regional hub that simplifies connectivity among many VPCs and on-prem networks (hub-and-spoke).

Gateway VPC Endpoint

Free gateway enabling private, in-region access to S3 or DynamoDB without an Internet or NAT gateway.

NAT Gateway

Managed service allowing private-subnet instances outbound Internet or AWS access while blocking inbound.

API Gateway Usage Plans

Feature that throttles and sets quotas for API keys to control customer usage and prevent runaway costs.

Data Transfer IN

Traffic entering AWS; generally free across almost all services and Regions.

Data Transfer OUT

Traffic leaving AWS to the Internet or other Regions/AZs; primary source of network charges.

Inter-AZ Data Transfer

Traffic that crosses Availability Zone boundaries within a Region; incurs a per-GB fee.

Pay-as-You-Go Pricing

AWS billing model where you pay only for resources consumed, with no up-front commitment.

Volume-Based Discounts

Automatic price reductions—e.g., for S3 or data transfer—when usage crosses defined tiers.

S3 Standard

Default S3 storage class for frequently accessed data; highest storage cost, zero retrieval fees.

S3 Standard-IA

Lower-cost tier for long-lived but infrequently accessed data that still requires rapid retrieval.

S3 One Zone-IA

Cheaper infrequent-access tier that stores data in a single AZ; suitable for reproducible data.

S3 Glacier Instant Retrieval

Archive tier providing millisecond access to rarely read objects at lower cost than Standard-IA.

S3 Glacier Flexible Retrieval

Low-cost archive tier with minutes-to-hours retrieval options; formerly ‘Glacier.’

S3 Glacier Deep Archive

Lowest-price storage class for long-term backups needing 12-hour restore time.

S3 Lifecycle Transition Action

Rule that moves objects to a different storage class after a set number of days to save money.

S3 Lifecycle Expiration Action

Rule that permanently deletes objects after a specified age to avoid indefinite storage fees.

Amazon Global Accelerator

Service that directs user traffic to optimal AWS endpoints via the AWS backbone to improve performance.

RequestCountPerTarget

Application Load Balancer metric showing average requests per registered target; useful for scaling triggers.

Amazon EBS

Persistent block-level storage for EC2 instances, supporting snapshots and multiple volume types.

gp3 Volume

EBS general-purpose SSD that offers baseline throughput and IOPS at lower cost than gp2, plus free tuning.

Provisioned IOPS (io2) Volume

Premium EBS SSD that delivers consistent, high IOPS for demanding workloads like large databases.

Amazon FSx

Family of fully managed file systems (e.g., Lustre, Windows, NetApp ONTAP) for specialized workloads.

Interface VPC Endpoint

Elastic Network Interface with private IPs in a subnet that privately connects to supported AWS services.