A fundamental problem and one of the most important abstractions for distributed and multi-agent systems is to achieve overall system reliability in the presence of a number of faulty processes, consensus. This often requires processes to agree on some data value that is needed during computation.
Consensus algorithm requires at least a mojority of nodes to be functioning correctly so that majority can for a quorum.
There's a termination property in consensus that is subject to the assumption that fewer than half of the nodes are crashed or unreachable, however, most implementations of consensus ensure that the safety properties - agreement, integrity and validity - are always met, even if the majority of nodes fail or there is a severe network problem, meaning that in case of a large scale outage can stop teh system from being able to process requests, but it cannot corrupt the consensus system by causing it to make invalid decisions.
Putting the aforementioned paragraph in example it means w