分布式系统设计.02new

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1、DistributedSystemsPrinciplesandParadigmsMaartenvanSteenVUAmsterdam,Dept.ComputerScienceRoomR4.20,steen@cs.vu.nlChapter02:ArchitecturesVersion:October25,2009ContentsChapter01:Introduction02:Architectures03:Processes04:Communication05:Naming06:Synchronizati

2、on07:Consistency&Replication08:FaultTolerance09:Security10:DistributedObject-BasedSystems11:DistributedFileSystems12:DistributedWeb-BasedSystems13:DistributedCoordination-BasedSystems2/25ArchitecturesArchitecturesArchitecturalstylesSoftwarearchitecturesAr

3、chitecturesversusmiddlewareSelf-managementindistributedsystems3/25Architectures2.1ArchitecturalstylesArchitecturalstylesBasicideaOrganizeintologicallydifferentcomponents,anddistributethosecomponentsoverthevariousmachines.LayerNObjectObjectLayerN-1ObjectMe

4、thodcallRequest Response flowflowObjectLayer2ObjectLayer1(a)(b)(a)Layeredstyleisusedforclient-serversystem(b)Object-basedstylefordistributedobjectsystems.4/25Architectures2.1ArchitecturalstylesArchitecturalStylesObservationDecouplingprocessesinspace(“anon

5、ymous”)andalsotime(“asynchronous”)hasledtoalternativestyles.ComponentComponentComponentComponentEventdeliveryDatadeliveryPublishEventbusPublishShared(persistent)dataspaceComponent(a)(b)(a)Publish/subscribe[decoupledinspace](b)Shareddataspace[decoupledinsp

6、aceandtime]5/25Architectures2.2SystemArchitecturesCentralizedArchitecturesBasicClient–ServerModelCharacteristics:Thereareprocessesofferingservices(servers)Thereareprocessesthatuseservices(clients)ClientsandserverscanbeondifferentmachinesClientsfollowreque

7、st/replymodelwrttousingservicesWaitforresultClientRequestReplyServerProvideserviceTime6/25Architectures2.2SystemArchitecturesApplicationLayeringTraditionalthree-layeredviewUser-interfacelayercontainsunitsforanapplication’suserinterfaceProcessinglayerconta

8、insthefunctionsofanapplication,i.e.withoutspecificdataDatalayercontainsthedatathataclientwantstomanipulatethroughtheapplicationcomponentsObservationThislayeringisfoundinmanydistributedinformationsystems,usingtraditio