In the last article I discussed about advance features and properties of SSIS namely Event Logging, Event Handlers, Transaction Support, Checkpoint Restart-ability and SSIS validation process. In this article, I am going to talk about SSIS architecture, SSIS buffer management, Types of transformation, execution tree and parallel processing. Understanding these things will let you understand internal of SSIS or how SSIS actually works. This knowledge will let you develop more performing package and optimize the package performance. In other words, for the purpose of troubleshooting SSIS issues (especially in the case of performance issues, exceptions, etc.) it is important to understand some high level concepts with respect to SSIS architecture.
The article continues at http://www.sql-server-performance.com/articles/biz/SSIS_An_Inside_View_Part_1_p1.aspx