Detecting system reconfiguration and maintaining persistent i/o configuration data in a clustered computer system

Abstract

In a clustered computer system with multiple power domains, a bus number manager within each power domain manages multiple nodes independently of other power domains. A node within a specified power domain includes a non-volatile memory that includes bus numbering information for its own buses as well as bus numbering information for two of its logically-interconnected neighbors. This creates a distributed database of the interconnection topology for each power domain. Because a node contains bus numbering information about its logical neighbor node(s), the bus numbers for the buses in the nodes are made persistent across numerous different system reconfigurations. The clustered computer system also includes a bus number manager that reads the non-volatile memories in the nodes during initial program load (i.e., boot) that reconstructs the interconnection topology from the information read from the non-volatile memories, and that assigns bus numbers to the buses according to the derived interconnection topology.