Tips and tricks from upgrading several sites from D6 to D7
Pentaho Data Integration Community Edition (PDI CE) also known as Kettle. Pentaho Data Integration delivers powerful Extraction, Transformation and Loading (ETL) capabilities using an innovative, metadata-driven approach. With an intuitive, graphical, drag and drop design environment, and a proven, scalable, standards-based architecture, Pentaho Data Integration is increasingly the choice for organizations over traditional, proprietary ETL or data integration tools.
The migrate module provides a flexible framework for migrating content into Drupal from other sources (e.g., when converting a web site from another CMS to Drupal). Out-of-the-box, support for creating Drupal nodes, users, and comments is included - hooks permit migration of other types of content.
How to convert a physical server to a virtual one using the open source tool Clonezilla Live