V Strong Replication in the GlobData Middleware

Strong Replication in the GlobData Middleware

L. Rodrigues, H. Miranda, R. Almeida, J. Martins and P. Vicente.

Selected sections of this report will be published in the Proceedings of the Workshop on Dependable Middleware-Based Systems, Washington D.C., USA, June 2002. (Part of Dependable Systems and Networks Conference, DSN 2002).


GlobData is a project that aims to design and implement a middleware tool offering the abstraction of a global object database repository. This tool, called Copla, supports transactional access to geographically distributed persistent objects independent of their location. Additionally, it supports replication of data according to different consistency criteria. For this purpose, Copla implements a number of consistency protocols offering different tradeoffs between performance and fault-tolerance.

This paper presents the work on strong consistency protocols for the GlobData system. Two protocols are presented: a voting protocol and a non-voting protocol. Both these protocols rely on the use of atomic broadcast as a building block to serialize conflicting transactions. The paper also introduces the total order protocol being developed to support large-scale replication.

Also available extended report (gzip postscript), (pdf) .

Luís Rodrigues