참고 답변
I've got extensive experience with various cloud migration strategies, adapting them based on the specific application and business needs. For a lift-and-shift approach, I managed the migration of an older SAP ERP system from an on-premise data center to AWS EC2 instances. We used AWS Server Migration Service (SMS) to replicate the virtual machines, which minimized downtime significantly. The main goal there was to quickly exit a costly data center lease without major refactoring. We set up VPN tunnels, configured security groups, and ensured network connectivity was robust before the final cutover. The process took about three months from initial assessment to full production readiness.
When refactoring was a better fit, I worked on a legacy monolithic e-commerce application. We broke down key components, like the product catalog and order processing, into microservices. I helped design the new architecture, moving the database from a self-managed Oracle instance to Amazon RDS for PostgreSQL, and deploying the new microservices onto Amazon EKS. This particular project took closer to nine months because it involved significant code changes and testing, but it resulted in much better scalability and reduced operational overhead. The team decided to refactor certain services first, like the recommendation engine, because it had independent scaling requirements and could provide immediate value as a standalone service. This allowed us to iterate and learn before tackling more complex parts of the monolith.
We also applied re-platforming for a document management system. It was running on Windows Server with SQL Server on-premise. I helped move the application servers to AWS EC2 using a more modern Windows AMI, and the SQL Server database to Amazon RDS for SQL Server. This wasn't a full refactor, but it took advantage of managed services for the database, reducing the DBA workload. We used native database migration tools and data replication to keep the databases in sync during the transition. The application itself needed minor configuration changes, primarily around connection strings and authentication, but the core code remained untouched. This strategy offered a good balance between cost and effort, providing immediate benefits from managed services without the heavy investment of a complete re-architecture.
I've also dealt with retiring applications that were no longer needed. We identified several low-usage internal tools that were simply consuming resources on-premise. After stakeholder approval, I oversaw the decommissioning process, ensuring all data was archived securely in Amazon S3 before shutting down the virtual machines. This helped clean up the environment and reduced the scope for future migrations, saving both time and money. Each strategy selection involved careful analysis of application dependencies, performance requirements, security needs, and of course, the total cost of ownership in the cloud versus on-premise. I always work closely with application owners and business stakeholders to ensure the chosen strategy aligns with their goals, whether it's cost savings, improved agility, or enhanced resilience.