Memory ushering in a scalable computing cluster

Scalable computing clusters (SCC) are becoming an alternative to mainframes and MPP's for the execution of high performance, demanding applications in multi-user, time-sharing environments. In order to better utilize the multiple resources of such systems, it is necessary to develop means for cluster wide resource allocation and sharing, that will make an SCC easy to program and use. This paper presents the details of a memory ushering algorithm among the nodes of an SCC. This algorithm allows a node which has exhausted its main memory to use available memory in other nodes. The paper first presents results of simulations of several algorithms for process placement to nodes. It then describes the memory ushering algorithm of the MOSIX multicomputer operating system for an SCC and its performance.