Managing event-based replication for abstract data types in distributed systems
Abdelsalam A. Heddaya · 1988
Data replication enhances the availability of data in distributed systems. This thesis deals with the management of a particular representation of replicated data objects that belong to Abstract Data Types (ADT). Traditionally, replicated data objects have been stored in terms of their states, or values. In this thesis, I argue for the viability of state transition histories, or logs, as a more suitable storage representation for abstract data types in distributed computing environments. We present two main contributions: a new protocol for reducing message and storage requirements of histories, and a novel reconfiguration and recovery method. In the first protocol, we introduce the notion of two phase gossip as the primary mechanism for managing distributed replicated event histories. We focus our second protocol for reconfiguration and recovery on enhancing the availability of distributed objects in the face of sequences of failures. Additionally, our reconfiguration protocol supports system administration functions related to the storage of distributed objects. In combination, the two protocols that we propose demonstrate the viability and desirability of the distributed representation of an ADT object as a history of the state transitions that the data undergoes, rather than as the value or the sequence of values that it assumes.