Consensus: The Big Misunderstanding
Rachid Guerraoui, André Schiper · 1997
The paper aims at clarifying some misunderstandings about the consensus problem. These misunderstandings prevent consensus from being considered as it should be, i.e., a fundamental paradigm in the context of fault-tolerant distributed systems, not only from a theoretical point of view, but also from a practical point of view. Six frequent misunderstandings are discussed. Misunderstanding 1: Consensus is for theoreticians only Consensus can be viewed as a general form of agreement in distributed systems [17]. The problem is defined over a set of processes fp 1 ; p 2 ; : : : ; pn g: each process p i has an initial value v i , and the correct processes (those that do not crash) have to decide on a common value v that is the initial value of one of the processes [3]. This problem has attracted theoreticians for over 15 years and has resulted in a large body of work, the most known being the Fischer, Lynch and Paterson result proving that consensus is not solvable in an asynchronous syst...