Specification of Replication Techniques, Semi-Passive Replication, and Lazy consensus*

This paper brings the following three main contributions: a hierarchy of specifications for replication techniques, semi-passive replication, and Lazy Consensus. Based on the definition of the Generic Replication problem, we difine two families of replication techniques: replication with parsimonious processing (e.g., passive replication), and replication with redundant processing (e.g., active replication). This helps relate replication techniques to each other. We define a novel replication technique with parsimonious processing, called semi-passive replication, for which we also give an algorithm. The most significant aspect of semi-passive replication is that it requires a weaker system model than existing techniques of the same family. We difine a variant of the Consensus problem, called Lazy Consensus, upon which our semi-passive replication algorithm is based. The main difference between Consensus and Lazy Consensus is a property of laziness which requires that initial values are computed only when they are actually needed.


    • LSR-REPORT-2002-009

    Record created on 2005-07-13, modified on 2017-05-12

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