Cheap Paxos

Asynchronous algorithms for implementing a fault-tolerant distributed system, which can make progress despite the failure of any F processors, require 2F + 1 processors. Cheap Paxos, a variant of the Paxos algorithm, guarantees liveness under the additional assumption that the set of nonfaulty processors does not "jump around" too fast, but uses only F + 1 main processors that actually execute the system and F auxiliary processors that are used only to handle the failure of a main processor. The auxiliary processors take part in reconfiguring the system to remove the failed processor, after which they can remain idle until another main processor fails.