Abstract: The block based data storage subsystem combines the functions of data storage/retrieval with block based data management functions, including but not limited to: Hierarchical Storage Management (HSM), Live Data Backup, Fault Tolerance, Capacity Planning, Performance Optimization and Dynamic Load Balancing. This system solves many storage management problems with a single technology and is completely independent from, and non intrusive to, the system it attaches to and has resources specifically designed to perform data management functions. The perspective of block data management is a much finer granularity and much simpler than existing data file based technologies.