The application of Systems Modeling (SysML) for Model Based Systems Engineering (MBSE) is now commonplace.  But many practitioners struggle with effective team collaboration as models and teams grow.  IBM has matured MBSE development practices with the introduction of IBM Engineering Systems Design Rhapsody - Model Manager. Model Manager is proven at enterprise scale - it can scale to support large teams (100+ users), large models, and sophisticated configuration management workflows.  This presentation will provide an overview of Rhapsody – Model Manager’s architecture, with insight into how it achieves stability and high performance, for multi-user management of model content and requirements traceability.