This presentation examines a complex strategic migration of a mission–critical COBOL banking application from Db2 z/OS hosted on IBM mainframe to Db2 LUW on Power Linux, drawing from a Polish banking institution's transformation initiative serving 12 million customers. We explore our comprehensive approach to database performance monitoring and capacity planning while migrating a 30+ TB database to a distributed architecture. The discussion focuses on practical methodologies for performance testing, benchmarking, and risk mitigation, highlighting key differences between Db2 z/OS and Db2 LUW environments. We will share our experience in addressing platform–specific considerations and architectural adaptations required for successful migration. Through real–world scenarios and lessons learned, attendees will gain actionable insights into our approach for designing monitoring frameworks and implementing effective migration strategies for similar large–scale database modernization projects.
