Abstract

In distributed systems, object replication is used to improve the availability and performance of applications in the presence of failures. When determining the configuration of a replicated object (i.e., number and location of replicas), a number of often conflicting factors need to be considered, e.g., the availability and performance requirements of the object. However, application specific knowledge about the objects, such as any inter-dependencies, is typically not accounted for. In many applications this information can affect an object's availability. Distributed systems which support replication typically give users only basic control over the configuration of a replicated object, such as the number or location of individual replicas. Expressing application specific knowledge is not possible. We have designed and implemented a replication sub-system allowing applications to control these aspects of replication. This system allows the efficient replication of an arbitrary umber of objects with arbitrary inter-dependencies.

Keywords

atomic actions, dynamic reconfiguration, object dependencies, object-oriented, replication