Migration strategies for large-scale legacy applications to AWS cloud ecosystems

As organizations strive to modernize their IT infrastructure and remain competitive in the digital economy, cloud migration has become a strategic necessity. Migrating large-scale legacy applications to cloud platforms like Amazon Web Services (AWS) offers advantages in scalability, resilience, performance, and cost optimization. However, legacy applications often present unique challenges due to outdated architectures, tight system coupling, and critical business dependencies. This review explores current migration strategies—including rehosting, replatforming, and refactoring—focusing on their effectiveness, decision frameworks, tools, performance outcomes, and risk mitigation. Through synthesis of academic literature, industrial case studies, and experimental evaluations, this paper provides a comprehensive overview of migration practices for legacy systems targeting AWS. Future research directions and open challenges are identified, encouraging a more automated, secure, and context-aware migration ecosystem.