The SMART-2 Array Controllers are based on an I/O Architecture which enables breakthrough capabilities for managing high performance storage. On-Line Capacity Expansion simplifies storage management by allowing on-line capacity expansion, eliminating the need to shut down the server while adding storage. Array Configuration Utility simplifies array configuration and facilitates on-line capacity expansion via a GUI interface. Array Performance Monitor monitors key parameters (with Compaq Insight Manager) and provides information for proactive system planning. Integrated components ensure continuous high-performance system access with ensured fault tolerance.