媒体存储技术-4存储基础iSCSI

COMMUNITCATIONUNIVERSITYOFCHINA,STORAGELABORATORYiSCSI:Past,Present,FutureLi-GuZhuDepartmentofComputerScience,CommunicationUniversityofChinaCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureVeryBriefHistory•Late1997–ideaofstorageoverIP–JulianSatran,IBMresearch•Late1999–IBMandCiscostartjointworkonproposalforstandard•Early2000–IETFcreatesIPstorageworkinggroup•November2000–IETFdraft0postedCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureRestofBriefHistory•Jan2001–SNIAcreatesIPstorageforum•July2001–firstUNHIOLiSCSIPlugtest–28companiesattended–Testeddrafts0and6•Feb2003–IETFapprovesdraft20•June2003–MicrosoftServerwithiSCSI•April2004–IETFpublishesRFC3720COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureToday•iSCSIproductsofferedbyallstorageandplatformvendors•Manysmallvendorsinthemarket•iSCSInowwellacceptedatlowandmiddleperformanceranges•1Gigwire-speedHBAsavailable•10GigiSCSIproductsstartingtoappearCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureOtherSANTechnologies•EnterprisedatacentersstillbasedonFibreChannel(4Gig,8Gig)•BiginterestinFCoE•WillFibreChannelequipmentpricesbelowerinthenearfuture??•InfiniBandCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureSCSITransportProtocolforTCP•Basedonwidelyused,off-the-shelftechnology–SCSI,TCP,IP,IPsec,Ethernet–Familiar,alreadyinstalledinfrastructure–Commoditycomponents,inexpensive•Permitsall-softwareimplementations–Encouragesexperimentation–ManyfreelydistributedimplementationsCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSI:RFC3720Document•Long,informalEnglishprose•Ambiguous,canbemisinterpreted•Testingislong,hasmanycombinations•Needforuseofformalmethodsforspecification,verification,testingCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSICOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIoverTCP/IPCommandSCSICommandDataCommandDataTCPHeaderTCPPayloadCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIApplications•Connectivity:iSCSIcanbeusedforDASorSANconnections.•iSCSIcapabledevicescouldbeplacedonanexistingLAN(sharedwithotherapplications)inasimilarwaytoNASdevices.•iSCSIcapabledevicescouldbeattachedtoaLANwhichisdedicatedtostorageI/O(inotherwordsanIPSAN),orevenonaLANconnectedtoonlyoneprocessor(likeaDAS).COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIHBAsandTCPOffloadEngines(TOEs)•OffloadsTCPand,optionally,iSCSIprocessingintohardware•RelieveshostCPUfrom:–TCPprocessing—16-bitchecksumperpacket–iSCSI—optional32-bitheaderanddatadigests(CRC32C)TCPOffloadiSCSIandTCPOffloadFileSystemBlockDeviceSCSIGenericHBADriverTCP/IPStackNICDriveriSCSIDriverTOEDriverSCSIAdapterAdapterDriverTCP/IPStackiSCSITCP/IPStackApplicationsCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIProtocolStackDataSCSIiSCSITCPIPEthernetPHYDriverTCPIPEthernetPHYDriverDataSCSIiSCSITCPIPEthernetPHYDriverDataSCSIiSCSIAdapterCardHostProcessingHostBusAdapter(HBA)SoftwareiSCSIiSCSITCPOffloadEngine(TOE)iSCSIHostBusAdapter(HBA)COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIPerformanceConsiderationCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureExampleperformanceimpactonCPUutil%FCvs.iSCSITOEvs.iSCSISWDriverCPU%ThroughputMB/sFCHBAiSCSITOEiSCSISWDriver15-35MB/sInflectionpointdeterminedbysystemresources(CPU/Memory)?COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureiSCSIBenefitCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureHostBusAdapter(FibreChannel)QLogicPCI-EXPRESS4Gb1PTFibreHostBusAdapter–STDFW•PCI-Express••1Port(FibreChannel)•DataRate:4Gb•StandardFirmwarePriceQuote:$951Source:(iSCSI)TheQLE4060CiSCSIHostBusAdapter(HBA)providesconnectivitytoSANsoverEthernetandTCP/IPnetworkinfrastructuresforPCIExpressbus-basedservers.Usingawidelydeployedandfamiliarnetworkingtechnology,iSCSIcanlowerthetotalcostofownershiptobettermanageandsupportstoragenetworking.Source::Past,Present,FutureMulti-TCPSessionsCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureHBA:Multi-PathI/OLUN:Logical[Storage]UnitsCOMMUNITCATIONUNIVERSITYOFCHINA,STORAGELABORATORYIsIP-SANsimilartoNAS?Whataretheadvantages,ifany,ofIP-SANvs.NAS?COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FuturePerformanceAnalysis:iSCSIvs.NAS(softwarebased–noHBA)iSCSINFSCOMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureSequentialRead/WriteTestsConclusion:1.Comparableperformanceincharacterread/writeandblockwrite2.SignificantadvantageofiSCSIinblockread(20-25%)COMMUNICAITONUNIVERSITYofCHINASTORAGYLABORATORYiSCSI:Past,Present,FutureSmallFilesRead/WriteCOMMUNICAITONUNIVERSI