Abstract

We determine what information about failures is necessary and sufficient to solve Consensus in asynchronous distributed systems subject to crash failures. In [CT91], it is shown that 3W, a failure detector that provides surprisingly little information about which processes have crashed, is sufficient to solve Consensus in asynchronous systems with a majority of correct processes. In this paper, we prove that to solve Consensus, any failure detector has to provide at least as much information as 3W. Thus, 3W is indeed the weakest failure detector for solving Consensus in asynchronous systems with a majority of correct processes.

Citations