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Article Summary:
Compare SQL Server on Amazon EC2 and Amazon RDS, then plan migration around control, availability, licensing and operations.
AWS offers two broad ways to run Microsoft SQL Server: a self-managed deployment on Amazon EC2 or the managed Amazon RDS for SQL Server service. Neither is automatically better. The right choice follows feature dependencies, control, resilience, licensing, skills and the amount of operational work the organisation wants to retain.
EC2 gives the broadest control
The AWS SQL Server overview positions EC2 for workloads that need operating-system access, custom agents, instance-level features or a familiar self-managed topology. Your team or service provider owns Windows, SQL Server configuration, patching, backups, high availability and recovery.
- Full host and instance administration
- Wider compatibility with existing tooling
- Customer-designed clustering or availability groups
- Greater customer operating responsibility
RDS trades control for managed operations
The RDS for SQL Server guide documents supported versions, Multi-AZ deployments, backups and service limitations. AWS handles more of the infrastructure and routine platform work. The managed boundary means some features, privileges and host integrations available on EC2 are not available in RDS.
Assess the workload before choosing
Inventory databases, instance-level objects, SQL Agent jobs, linked servers, CLR, SSIS, reporting, file access, encryption, maintenance, authentication and third-party agents. Confirm each dependency against current target documentation. Estimate CPU, memory, storage throughput, IOPS, backup volume and peak concurrency from observed data.
Design availability as an application service
A Multi-AZ database or an EC2 availability group addresses part of the failure path. Test DNS, connection strings, retries, transactions, jobs and dependencies during failover. Define region recovery separately where the business requires it. Record who operates each layer and how incidents are escalated.
Rehearse migration and rollback
AWS's prescriptive migration pattern illustrates a native backup and restore path to RDS. Other methods may suit lower downtime or different sources. Rehearse with production-like volume, validate users and jobs, compare performance, test recovery and set a clear rollback point.
- Compatibility and feature gate
- Landing-zone and security checks
- Full-volume migration rehearsal
- Application and performance acceptance
- Cutover, reconciliation and rollback
Talk to a database specialist
A change to support, licensing, cloud architecture or a production database should be based on evidence from your own estate. Pro DBA can assess the current position, identify the material risks and help you plan the next step. Contact the Pro DBA team to discuss your environment.
