PERFORMANCE ISSUES IN OBJECT REPLICATION FOR A REMOTE CACHING ARCHITECTURE

The high performance networks in modern distributed systems enable a site to obtain cached objects from the main memory of other sites more quickly than the time needed to access local disks. In this environment, efficient mechanisms can be devised to support rapid request/response exchanges for objects that reside on remote sites. As a result, it becomes possible to use remote memory as an additional layer in the memory hierarchy between local memory and disks. This paper studies the effect of policies on cache performance in a remote caching architecture. A key issue is managing the number of object replicas maintained by different sites. Although exploiting remote memory improves performance over a wide range of cache sizes as compared to a distributed client/server caching architecture, efficient use of remote memory can be difficult to achieve. We develop an analytical model of system performance in a remote caching architecture, and identify critical system parameters affecting this performance. Performance evaluation can guide system designers in selecting the appropriate cache replacement and cache management policies for this environment. Several policies are examined, and their effect on both overall and local system performance is described.