Amazon DynamoDB offers two billing modes: On-Demand and Provisioned. While On-Demand capacity provides flexibility, provisioned capacity can significantly reduce costs for applications with consistent workloads.
Why This Policy Matters
Cost Optimization Strategies
- Predictable Workloads: Ideal for applications with consistent traffic patterns
- Capacity Planning: Enables precise resource allocation
- Budget Control: Provides more granular cost management
Financial Impact
A typical 100GB DynamoDB table with the following characteristics demonstrates significant savings:
- 5,000 Read Capacity Units (RCUs)
- 2,000 Write Capacity Units (WCUs)
- 50 million reads per day
- 20 million writes per day
Cost Comparison:
- Provisioned Capacity: $1,400/month
- On-Demand Capacity: $2,600/month
- Potential Savings: 46%
Implementation Guide
Infrastructure as Code Example (Terraform)
Before:
resource "aws_dynamodb_table" "example" {
billing_mode = "PAY_PER_REQUEST" # On-Demand Mode
name = "MyTable"
hash_key = "ID"
attribute {
name = "ID"
type = "S"
}
}After:
resource "aws_dynamodb_table" "example" {
billing_mode = "PROVISIONED" # Provisioned Mode
name = "MyTable"
read_capacity = 5000
write_capacity = 2000
hash_key = "ID"
attribute {
name = "ID"
type = "S"
}
}Manual Implementation Steps
- Analyze historical traffic patterns
- Calculate average read and write capacity requirements
- Switch billing mode to Provisioned
- Set initial read/write capacity units
- Enable auto-scaling for dynamic adjustment
Best Practices
- Monitor Performance: Use CloudWatch metrics
- Enable Auto-Scaling: Automatically adjust capacity
- Regular Review: Quarterly workload assessments
- Use Reserved Capacity: Additional cost savings for long-term commitments
Tools for Implementation
- AWS CloudWatch: Performance monitoring
- Infracost: Identify and prevent costly configurations
- AWS Cost Explorer: Analyze spending patterns
Example Scenarios
E-commerce Platform
- Workload: Consistent daily traffic
- Benefit: Predictable capacity planning
- Estimated Savings: 40-50% compared to On-Demand
SaaS Application
- Workload: Regular user interactions
- Benefit: Optimized resource allocation
- Estimated Savings: 35-45% reduction in database costs
Considerations and Caveats
Potential Drawbacks
- Requires more upfront planning
- Risk of under-provisioning
- Initial configuration complexity
When to Avoid
- Highly unpredictable workloads
- Startup applications with unknown traffic patterns
- Infrequently accessed tables
Infracost Integration
Infracost’s free trial helps you:
- Scan existing infrastructure
- Identify cost optimization opportunities
- Provide instant recommendations for DynamoDB configurations