# MSFTREL01-BP02 Align your architectural design with your availability needs and capacity demands
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 There are architecture recommendations regarding Microsoft workloads, whether addressing Windows infrastructure, Active Directory, SQL Server databases, .NET applications, or other technologies. Review the vendor recommendations along with AWS documentation to verify that your application is running with best practices to improve availability and resiliency. 

 **Desired outcome:** A Microsoft workload optimized for high availability and scalability and aligned with vendor recommendations and AWS best practices. This strategy verifies that the system meets availability targets and capacity demands efficiently, while remaining resilient and maintainable. 

 **Common anti-patterns:** 
+  Directly migrating Microsoft workloads to AWS without redesigning for cloud capabilities, resulting in missed opportunities for improved availability and automated scaling. 
+  Ignoring Microsoft's recommended high-availability configurations (like Always On Availability Groups for SQL Server) in favor of simplified single-instance deployments. 
+  Treating AWS Regions as simple datacenter replacements rather than using multi-AZ and Regional resilience patterns specific to AWS infrastructure. 

 **Benefits of establishing this best practice:** 
+  Increased system reliability through proven architectural patterns, reducing downtime and improving customer satisfaction while lowering operational overhead. 
+  Optimized cost-efficiency by properly sizing resources and utilizing AWS's elastic scaling capabilities, avoiding over-provisioning while maintaining performance. 
+  Enhanced disaster recovery capabilities through AWS-specific resilience features combined with Microsoft's high-availability solutions, maintaining business continuity. 

 **Level of risk exposed if this best practice is not established:** High 

## Implementation guidance
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 Document your current Microsoft workload architecture and availability needs, and consult AWS and Microsoft best practices for your specific technologies. 

 Develop a phased migration plan incorporating these recommendations, prioritizing critical components. 

 Use AWS managed services where possible and implement multi-AZ deployments. 

 Regularly test resilience and conduct Well-Architected reviews to align with best practices. 

### Implementation steps
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1.  Evaluate SQL Server Always On Availability Groups configuration, Active Directory domain controller placement, Exchange Database Availability Groups, SharePoint farm topology, and .NET application dependencies. Document current RTO/RPO requirements and identify single points of failure in your Microsoft workload stack. 

1.  Implement SQL Server Always On across multiple Availability Zones using Amazon EC2 or Amazon RDS Multi-AZ, deploy Active Directory domain controllers in separate Availability Zones with AWS Managed Microsoft AD integration, establish Exchange DAG with cross-AZ mailbox databases, and design .NET applications for stateless operation with Application Load Balancer distribution. For more detail, see [Microsoft workload architecture patterns](https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/microsoft-workloads.html). 

1.  Replace self-managed components with Amazon RDS for SQL Server, AWS Managed Microsoft AD, Amazon FSx for Windows File Server, and AWS Systems Manager for Windows patch management. This reduces operational overhead while improving availability through AWS-managed infrastructure resilience. 

1.  Configure SQL Server Always On listener endpoints across Availability Zones, establish Active Directory site topology aligned with Availability Zones, implement Exchange transport high availability, and verify that .NET applications handle Availability Zone failures gracefully. Reference [Microsoft SQL Server on AWS best practices](https://docs.aws.amazon.com/prescriptive-guidance/latest/sql-server-ec2-best-practices/welcome.html). 

1.  Test SQL Server failover scenarios, Active Directory replication across Availability Zones, Exchange mailbox database switchovers, and .NET application resilience to infrastructure failures. Establish automated testing procedures that validate both AWS infrastructure and Microsoft application layer availability. 

## Resources
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 **Related documents:** 
+  [Design your workload service architecture](https://docs.aws.amazon.com/wellarchitected/latest/reliability-pillar/design-your-workload-service-architecture.html)