Volatile logging in n-fault-tolerant distributed systems

The authors introduce two enhancements to optimistic recovery which allow messages to be logged without performing any I/O to stable storage. The first permits messages to be instantaneously logged in volatile storage, as in the sender-based message logging technique of D.B. Johnson and W. Zwaenepoel (1987), but without their restriction of single-fault-tolerance. The second permits message data and/or message arrival orders not to be logged in circumstances where this information can be reconstructed in other ways. They show that the combination of these two optimizations yields a transparent n-fault-tolerant system which logs to stable storage only those messages received from the outside world and a very small number of additional messages.<>