### Module 4: Cluster Sizing and Resource Allocation
#### Lesson 1: Translating Business Requirements into Cluster Specifications
**Objective**: Teach how to interpret business needs and translate them into technical specifications for an OpenSearch cluster.
**Topics**:
- **Understanding Business Objectives**: Overview of common business objectives that influence cluster design, such as search performance, data retention policies, and scalability requirements.
- **Capacity Planning**: Introduction to capacity planning, including estimating data volume growth, query load, and the impact of these factors on cluster size and configuration.
- **Performance Objectives**: Defining performance metrics and objectives, such as query response times and indexing throughput, and how they impact cluster specifications.
- **Availability and Reliability**: Considerations for high availability and disaster recovery planning in cluster design.
#### Lesson 2: Rightsizing for Cost-Effectiveness and Performance
**Objective**: Provide strategies and tools for rightsizing OpenSearch clusters to balance cost with performance and operational needs.
**Topics**:
- **Rightsizing Principles**: Key concepts in rightsizing, including starting small, iterative testing, and scaling.
- **Monitoring and Metrics**: Utilizing performance metrics and monitoring tools to inform rightsizing decisions.
- **Scaling Strategies**: Detailed look at horizontal vs. vertical scaling, including when to choose each strategy based on different scenarios.
- **Cost Optimization Techniques**: Techniques for cost-saving, such as choosing the appropriate instance types, leveraging reserved instances or savings plans, and optimizing storage.
#### Lesson 3: Storage and Memory Considerations
**Objective**: Dive into the specifics of managing storage and memory in OpenSearch clusters, crucial for performance and scalability.
**Topics**:
- **Storage Types and Options**: Overview of storage options (e.g., SSD vs. HDD) and their impact on performance.
- **Estimating Storage Needs**: Techniques for estimating storage requirements based on data volume, indexing overhead, and replication.
- **Memory Management**: Understanding the relationship between memory and performance in OpenSearch, including heap size configuration and garbage collection tuning.
- **Data Lifecycle Management**: Introduction to strategies for managing the lifecycle of data in OpenSearch, such as index rollover and deletion policies to manage storage efficiently.