language: en

Semantics-based Failure Recovery in Distributed Systems with Optimistic Message Logging

Hong Va Leong Divyakant Agrawal
Department of Computer Science University of California
Santa Barbara, CA 93106

Abstract Recovery from failures is important in distributed computing. A common technique to support recovery is asynchronous checkpointing, coupled with optimistic message logging. These schemes have low overheads during failure-free operations and can provide an acceptable degree of fault-tolerance. Central to these protocols is the determination of a maximal consistent global state, which is recoverable. Message semantics is not exploited in most existing recovery protocols to determine the recoverable state. We propose to identify messages that are not influential in the computation through message semantics. These messages can be logically removed from the computation without changing its meaning or result. In this paper, we illustrate with examples how the removal of these messages improves the theoretical maximal consistent global state. Taking semantics into account, recovery protocols are then developed to realize the idea. The semantics in object-oriented databases is adapted to special processes acting as servers for further improvements. This technique can also be applied to ensure a more timely commitment for output in a distributed computation.

Keywords: message semantics, commutativity, recovery, optimistic message logging, asynchronous checkpointing

[An abridged version of this paper appears in the]

[Proceedings of the 14th International Conference on Distributed Computing Systems as Using Message Semantics to Reduce Rollback in Optimistic Message Logging Recovery Schemes.]

[This research is supported in part by the NSF under grant number IRI-9117094.]