Amazon EC2 instances consolidation for Microsoft SQL Server

This Recommendation identifies opportunities to consolidate Microsoft SQL Server licenses on Amazon EC2 instances by using instances with more vCPUs to reduce licensing costs.

Note on Cost Impact: This Recommendation calculates estimated savings based on SQL Server licensing inefficiency. The calculation uses:

Inefficiency Ratio = (Minimum vCPU - Current vCPU) / Minimum vCPU
Estimated Savings = Instance Cost × Inefficiency Ratio × 0.30

The 0.30 factor represents an estimate that SQL Server licensing comprises approximately 30% of total EC2 instance costs. For example, an instance with 1 vCPU but requiring 4 vCPU minimum (75% inefficiency) costing $100/month would show estimated savings of $22.50/month ($100 × 0.75 × 0.30). Actual savings will vary based on your specific licensing agreements and instance types.

What it does

This Recommendation analyzes your EC2 instances running Microsoft SQL Server and identifies cases where:

Instances are running with fewer vCPUs than the minimum required for SQL Server licensing
Multiple smaller instances could be consolidated into larger instances to optimize licensing costs
SQL Server editions (Standard, Enterprise, etc.) could benefit from instance consolidation

Microsoft SQL Server licensing is often based on core/vCPU counts, and there are minimum licensing requirements. By consolidating workloads onto instances with more vCPUs that meet or exceed these minimums, you can potentially:

Reduce the total number of SQL Server licenses needed
Improve SQL Server performance through better resource allocation
Simplify management by reducing the number of instances

Why it matters

License Cost Optimization: SQL Server licensing costs can be substantial, especially for Enterprise Edition. Consolidating instances can significantly reduce licensing expenses
Infrastructure Efficiency: Running fewer, larger instances can be more cost-effective than many smaller instances
Performance: Properly sized instances with adequate vCPUs can improve SQL Server performance
Management Overhead: Fewer instances mean less administrative overhead for patching, monitoring, and maintenance

Recommended actions

Review Recommendations: Examine the specific instances flagged by Trusted Advisor, noting their:
- Current instance type and vCPU count
- SQL Server edition in use
- Minimum recommended vCPU count for optimal licensing
Analyze Workloads: Assess whether the SQL Server workloads on flagged instances can be:
- Consolidated onto larger instance types
- Combined with other SQL Server instances
- Migrated to instances that better match licensing tiers
Plan Consolidation: Develop a migration plan that:
- Identifies target instance types with appropriate vCPU counts
- Groups compatible SQL Server workloads together
- Schedules migrations during maintenance windows
- Includes rollback procedures
Test Changes: Before production implementation:
- Validate SQL Server performance on consolidated instances
- Verify license compliance with new configuration
- Test application connectivity and functionality
Implement Changes: Execute the consolidation during scheduled maintenance windows:
- Backup all databases before migration
- Follow SQL Server best practices for instance migration
- Update monitoring and backup configurations
Monitor and Optimize: After consolidation:
- Track SQL Server performance metrics
- Verify cost savings from licensing optimization
- Monitor resource utilization to ensure adequate capacity
- Document the new configuration for future reference

Additional Considerations

Licensing Models: Ensure compliance with Microsoft SQL Server licensing agreements when consolidating instances
High Availability: Consider the impact on your high availability and disaster recovery strategy when consolidating instances
Resource Isolation: Evaluate whether workload consolidation aligns with your security and isolation requirements
Performance Testing: Conduct thorough performance testing to ensure consolidated instances meet application requirements