分布式系统设计.08

《分布式系统设计.08》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。

1、DistributedSystemsPrinciplesandParadigmsMaartenvanSteenVUAmsterdam,Dept.ComputerScienceRoomR4.20,steen@cs.vu.nlChapter08:FaultToleranceVersion:December2,2009ContentsChapter01:Introduction02:Architectures03:Processes04:Communication05:Naming06:Synchronization07:Con

2、sistency&Replication08:FaultTolerance09:Security10:DistributedObject-BasedSystems11:DistributedFileSystems12:DistributedWeb-BasedSystems13:DistributedCoordination-BasedSystems2/65FaultToleranceIntroductionBasicconceptsProcessresilienceReliableclient-servercommunic

3、ationReliablegroupcommunicationDistributedcommitRecovery3/65FaultTolerance8.1IntroductionDependabilityBasicsAcomponentprovidesservicestoclients.Toprovideservices,thecomponentmayrequiretheservicesfromothercomponents)acomponentmaydependonsomeothercomponent.Specifical

4、lyAcomponentCdependsonCifthecorrectnessofC’sbehaviordependsonthecorrectnessofC’sbehavior.Note:componentsareprocessesorchannels.AvailabilityReadinessforusageReliabilityContinuityofservicedeliverySafetyVerylowprobabilityofcatastrophesMaintainabilityHoweasycanafail

5、edsystemberepaired4/65FaultTolerance8.1IntroductionTerminologySubtledifferencesFailure:Whenacomponentisnotlivinguptoitsspecifications,afailureoccursError:Thatpartofacomponent’sstatethatcanleadtoafailureFault:ThecauseofanerrorWhattodoaboutfaultsFaultprevention:preve

6、nttheoccurrenceofafaultFaulttolerance:buildacomponentsuchthatitcanmaskthepresenceoffaultsFaultremoval:reducepresence,number,seriousnessoffaultsFaultforecasting:estimatepresentnumber,futureincidence,andconsequencesoffaults5/65FaultTolerance8.1IntroductionFailuremod

7、elsFailuresemanticsCrashfailures:Componenthalts,butbehavescorrectlybeforehaltingOmissionfailures:ComponentfailstorespondTimingfailures:Outputiscorrect,butliesoutsideaspecifiedreal-timeinterval(performancefailures:tooslow)Responsefailures:Outputisincorrect(butcanatl

8、eastnotbeaccountedtoanothercomponent)Valuefailure:WrongvalueisproducedStatetransitionfailure:ExecutionofcomponentbringsitintoawrongstateArbitraryfailure