The document details a case study on a large-scale migration project involving the transition of 4 TB of data from Microsoft SharePoint Portal Server 2003 to SharePoint Server 2010, completed in 2.5 months. It outlines the challenges faced, such as limited system changes allowed, file size limitations, and the need for extensive preparation and custom tools to manage the migration effectively. Key success factors included a customer-oriented approach, strong communication, and the use of third-party tools like AvePoint DocAve to facilitate the process.