Scalable Load-Sharing for Distributed Systems

Adaptive algorithms for load-sharing usually comprise two basic functions: state information dissemination and decision making (control). This paper describes a flexible load-sharing algorithm, FLS, which includes a third function introduced for scalability purposes, that of partitioning into domains. The system partitioning function at a node is responsible for the selection of other nodes to be included in its domain. The state of other nodes in its domain is held locally, in a cache. Cached data is treated as hints for decision making. The FLS algorithm permits local decisions to be made, aims at minimising the number of incorrect decisions and does not allow erroneous decisions to proceed. The algorithm is analysed and shown to be stable and scalable. Its suitability to a CONIC/REX environment is demonstrated with a prototype implementation, providing an automatic software allocation service as part of configuration management.