IBM V系统存储 hyperswap实施手册(英文)

'IBMV系统存储hyperswap实施手册19 文档信息(文档编号IBMSVC-70)文挡名称作者电话QQIBMV系统存储hyperswap实施手册朱亚铭13951968365150111099文档修订记录编号修订内容简述修订日期修订前版本号V1.0整体文档的编写2016.12.23注：技术交流邮箱ymzhu2005@163.com19 一、ConfiguringanIBMHyperSwaptopologysystem窗体顶端窗体底端AHyperSwap®topologysystemassistswithhighavailabilityandsitedisasterrecovery.AHyperSwaptopologysystemcanbeconfiguredthroughsiteallocationandtopologychangecommand-line(CLI)commands.ThemanagementGUIconfiguresaHyperSwaptopologywiththeModifySystemTopologywizard,whichguidesyouthroughallthestepseasily.1.1AboutthistaskToaccesstheModifySystemTopologywizard,selectMonitoring>System.IntheActionsmenu,selectModifySystemTopology.·ConfiguringsiteinformationforthesystemToconfigureaHyperSwapsystemtopology,youmustassignenclosures,externalstoragesystems,andhoststoaspecificsite.·CreatingHyperSwapvolumesYoucanusethemanagementGUIorthecommand-lineinterface(CLI)tocreateHyperSwapvolumes.AHyperSwapvolumehasonecopyoneachsite.·ConvertinganexistingvolumetoaHyperSwapvolumeYoucanusethemanagementGUIorthecommand-lineinterfacetoconvertabasicvolumetoaHyperSwapvolume.Youconvertthebasicvolumebyaddinganothercopyofthevolumeinasecondsite.二、Configuringsiteinformationforthesystem窗体顶端窗体底端ToconfigureaHyperSwap®systemtopology,youmustassignenclosures,externalstoragesystems,andhoststoaspecificsite.19 2.1UsingthemanagementGUIYoucanusetheModifySystemTopologywizardinthemanagementGUItoeasilyconfigurethesitenamesandassignobjectsonyoursystemtoasite.TheModifyTopologywizardautomaticallydetectsanyFibreChannel-attachedstorage,butiSCSIstoragemustbeaddedmanuallybeforethesiteassignmentscanbeconfigured.YoucanuseeitherthemanagementGUIorthecommand-lineinterfacetoaddStorwizesystems.DellEqualLogficsystemscanbeconfiguredwiththecommand-lineinterfaceonly.CompletethefollowingstepstoconfigurethetopologyforthesystemandtooptionallyaddiSCSI-attachedstorage:1.InthemanagementGUI,selectMonitoring>System.IntheActionsmenu,selectModifySystemTopology.2.FollowthewizardtocompletetheconfigurationoftheHyperSwaptopology.3.IfyouareusingiSCSI-attachedexternalstorage,youmustaddthestoragetothesystemandspecifythesiteusingtheAddiSCSIExternalStoragewizard.Toaccessthewizard,selectPools>ExternalStorage>AddiSCSIExternalStorage.4.SelectIBMStorwizeastheexternalstoragesystemthatyouareadding.ThesystemsupportsiSCSIconnectionstoStorwizefamilyproductsandtoDellEquallogicsystems,butyoumustconfigureDellEqualLogicsystemswiththecommand-lineinterface.5.EntertheinformationforthesourceandtargetportsfortheiSCSIconnectionandspecifythesitefortheiSCSI-attachedstorage.2.2UsingtheCLIYoucanalsousethecommand-lineinterfacetoconfiguresiteinformationandconfigurethesystemasaHyperSwaptopology.Separatecommandsareusedforeachconfiguringsitedefinitionsforthenecessaryobjectsonthesystem.Althoughyoudonotneedtonamesites,creatingnamesthatarebasedonthelocationoruseofthesitesimplifiesmanagementoftheHyperSwaptopology.CompletethefollowingstepstoconfiguresiteinformationandsetthesystemasaHyperSwaptopology:1.ForeasiermanagementoftheHyperSwaptopology,createspecificnamesforeachsiteonthesystem.Ifnamesarenotspecified,sitescanbereferredtobytheirdefaultnameornumericID.Enterthefollowingcommandtocreatespecificnamesforeachsite.chsite-namelosangeles119 Inthisexample,site1isnownamedlosangeles.TorenametheothersitesintheHyperSwaptopology,issuethesamecommandwithnamesfortheothersites:chsite-namesandiego2chsite-namequorum3Inthisexample,site2isnownamedsandiegoandsite3isnamedquorum.Note:IPquorumapplicationscanbeusedatathirdsitetoprovideatie-breakifthereisalossofconnectivitybetweensite1andsite2.Formoreinformation,seetheIPquorumconfigurationinformation.1.Enterthefollowingcommandstoassignexistingnodecanistersineachcontrolenclosure(I/Ogroup)tosites:chnodecanister-sitelosangelescanister1chnodecanister-sitelosangelescanister2Bothnodecanistersinacontrolenclosuremustbeassignedtothesamesite.Inthisexample,theI/Ogroupthatcontainscanister1andcanister2areassignedtothesitelosangeles.ToassignthenodecanistersinanotherI/Ogrouptotheothersite,enterthefollowingcommands:chnodecanister-sitesandiegocanister3chnodecanister-sitesandiegocanister4Inthisexample,theI/Ogroupthatcontainscanister3andcanister4areassignedtothesitesandiego.Youmustassignasiteforallnodecanistersinthesystem.2.Enterthefollowingcommandtoassignexistingexternalstoragesystemstosites:chcontroller–sitelosangelesstoragesystem1Inthisexample,storagesystem1isassignedtositelosangeles.Toassignastoragesystemtotheothersite,enterthefollowingcommand:chcontroller–sitesandiegostoragesystem2Inthisexample,storagesystem2isassignedtositesandiego.19 Ifyouplantouseanexternalstoragesystemtoprovidequorum,thenyoumustassignthattothethirdsite.Alternatively,anIPquorumapplicationcanbeusedtoprovidequorum.Formoreinformation,seetheIPquorumconfigurationinformation.Toassignanexternalstoragesystemtothethirdsite,enterthefollowingcommand:chcontroller–sitequorumstoragesystem3Inthisexample,storagesystem3isassignedtositequorum.Youmustassignasiteforallstoragesystemsthatarepresentintheconfiguration.1.Enterthefollowingcommandtoassignexistinghoststosites:chhost-sitelosangeleshost1Inthisexample,host1isassignedtositelosangeles.Ifyouhaveotherhosts,youcanassignthemtoothersites:chhost-sitesandiegohost2Inthisexample,host2isassignedtositesandiego.2.Afterallthesiteassignmentsarecompleteforenclosures,storagesystems,andhosts,setthesystemtopologytoHyperSwapbyenteringthefollowingcommand:chsystem-topologyhyperswap3.Optionally,configurebandwidthsettingsforthebackgroundcopyoperationsbetweeneachsitebyenteringthefollowingcommand:chpartnership-linkbandwidthmbits2048-backgroundcopyrate50mysystemBackgroundcopyisthetermthatisusedfortheinitialsynchronizationandanysubsequentresynchronizationtrafficforHyperSwapvolumesinthesystem.Afteryoucompletethesesteps,youcanconfigureHyperSwapvolumestocreatecopiesateachsite.19 2.3ConfiguringanexternaliSCSIcontrollerusingtheCLIAfteryouchangethesystemtopologytohyperswapandnodesareassignedsites,youcanconfigureanexternaliSCSIcontrollerbycompletingthefollowingsteps.1.Fromthenodesofsite1,discovertheiSCSItargetcontroller:2.detectiscsistorageportcandidate–srcportid1-targetipIP1-site13.Checkthestatusofthediscoveredtargets:4.lsiscsistorageportcandidateidsrc_port_idtarget_ipv4|target_ipv65.target_iscsinameiogroup_listconfiguredstatussite_idsite_name01IP1IQN11:1:1:1noFull1site16.Fromthenodesofsite1,addasessiontothediscoveredtargets:addiscsitorageport-site107.Fromthenodesofsite1,viewtheestablishedsessionswiththetarget:8.idsrc_port_idtarget_ipv4|target_ipv6target_iscsiname9.controller_idiogroup_liststatussite_idsite_name03IP1IQN151:1:1:1full1site110.Thenewcontrollercanbeshownasavailablebyenteringthelscontrollercommand.Assignasite:chcontroller-site1controllerID11.Fromthesystemnodesofsite2,repeatsteps1through5fordiscoveringandestablishingsessionstothesameiSCSIcontrolleroradifferentiSCSIcontroller.三、CreatingHyperSwapvolumes窗体顶端窗体底端YoucanusethemanagementGUIorthecommand-lineinterface(CLI)tocreateHyperSwap®volumes.AHyperSwapvolumehasonecopyoneachsite.19 3.1BeforeyoubeginBeforeyoucreateHyperSwapvolumes,youmustconfiguretheHyperSwaptopology.SeeConfiguringsiteinformationforthesystemfordirections.3.2AboutthistaskAfteryouconfiguretheHyperSwaptopology,completeoneofthefollowingsteps.3.3Procedure1.IfyouareusingthemanagementGUI,usetheCreateVolumeswizardtocreateHyperSwapvolumes.2.Ifyouareusingthecommand-lineinterface,usethemkvolumecommandtocreateavolume.Forexample,aHyperSwapvolumeiscreatedbyspecifyingtwostoragepoolsinindependentsites.mkvolume-size100-poolsite1pool:site2pool四、ConvertinganexistingvolumetoaHyperSwapvolume窗体顶端窗体底端YoucanusethemanagementGUIorthecommand-lineinterfacetoconvertabasicvolumetoaHyperSwap®volume.Youconvertthebasicvolumebyaddinganothercopyofthevolumeinasecondsite.4.1BeforeyoubeginBeforeyouaddacopyofthevolume,thesystemmustbeconfiguredwiththeHyperSwapsystemtopology.4.2AboutthistaskUsingthemanagementGUI:19 TochangeabasicvolumetoaHyperSwapvolumeinthemanagementGUI,selectVolumes,right-clickthebasicvolume,andselectAddVolumeCopies.Addacopyinadifferentsitetotheexistingcopy.Usingthecommand-lineinterface(CLI):IntheCLI,theaddvolumecopycommandaddsacopytoaHyperSwapvolume,whichchangesabasicvolumeintoaHyperSwapvolumewithcopiesontwoseparatesites.ToaddacopytoabasicvolumetoconvertittoaHyperSwapvolume,enterthefollowingcommand:addvolumecopy-poolsite2poolvolume5Inthisexample,site2poolisthestoragepoolontheothersite.AquorumdiskisanMDiskoramanageddrivethatcontainsareservedareathatisusedexclusivelyforsystemmanagement.Asystemusesaquorumdiskfortwopurposes:·TobreakatiewhenaSANfaultoccurs,whenexactlyhalfofthenodesthatwerepreviouslyamemberofthesystemarepresent.·Toholdacopyofimportantsystemconfigurationdata.Justover256MBisreservedforthispurposeoneachquorumdiskcandidate.·QuorumdiskconfigurationAclusteredsystemautomaticallyassignsquorumdiskcandidates.Whenyouaddnewstoragetoasystemorremoveexistingstorage,however,itisagoodpracticetoreviewthequorumdiskassignments.·IPquorumconfigurationInsomeHyperSwap®configurations,IPquorumapplicationscanbeusedatthethirdsiteasanalternativetothird-sitequorumdisks.·ManualquorumdiskoverrideinaHyperSwapsystemAmanualquorumdiskoverrideisrequiredwhenyouexperiencearollingdisaster.Inraresituations,thesystemissubjecttowhatisreferredtoasarollingdisaster.Arollingdisasteroccurswhenanincidenthaswidescope,anditseffectsarefeltinmultiplestepsoveranextendedtimeperiod.Thefollowingexamplescenariodescribesarollingdisasterandshowshowtorecoverfromthatrollingdisaster.19 五、Quorumdiskconfiguration窗体顶端窗体底端Aclusteredsystemautomaticallyassignsquorumdiskcandidates.Whenyouaddnewstoragetoasystemorremoveexistingstorage,however,itisagoodpracticetoreviewthequorumdiskassignments.Itispossibleforasystemtosplitintotwogroupswhereeachgroupcontainshalftheoriginalnumberofnodesinthesystem.AquorumdiskdetermineswhichgroupofnodesstopsoperatingandprocessingI/Orequests.Inthistie-breaksituation,thefirstgroupofnodesthataccessesthequorumdiskismarkedastheownerofthequorumdiskandasaresultcontinuestooperateasthesystem,handlingallI/Orequests.Iftheothergroupofnodescannotaccessthequorumdiskorfindsthequorumdiskisownedbyanothergroupofnodes,itstopsoperatingasthesystemanddoesnothandleI/Orequests.Asystemcanhaveonlyoneactivequorumdiskthatisusedforatie-breaksituation.However,thesystemusesthreequorumdiskstorecordabackupofsystemconfigurationdatatobeusedintheeventofadisaster.Thesystemautomaticallyselectsoneactivequorumdiskfromthesethreedisks.Theactivequorumdiskcanbespecifiedbyusingthechquorumcommand-lineinterface(CLI)commandwiththeactiveparameter.Toviewthecurrentquorumdiskstatus,usethelsquorumcommand.Theotherquorumdiskcandidatesprovideredundancyiftheactivequorumdiskfailsbeforeasystemispartitioned.Toavoidthepossibilityoflosingallthequorumdiskcandidateswithasinglefailure,assignquorumdiskcandidatesonmultiplestoragesystems.Note:Mirroredvolumescanbetakenofflineifnoquorumdiskisavailable.Thesynchronizationstatusformirroredvolumesisrecordedonthequorumdisk.Important:Makesurethatyoumoveanyquorumdiskstoadifferentcontrollerbeforeyoudomaintenanceonaservicecontroller.InaStorwize®V5000systemwithasinglecontrolenclosureorwithoutanyexternalmanageddisks,quorumisautomaticallyassignedtodrives.Inthisscenario,manualconfigurationofthequorumdisksisnotrequired.InasystemwithtwoormoreI/Ogroups,thedrivesarephysicallyconnectedtoonlysomeofthenodecanisters.Insuchaconfiguration,drivescannotactastie-breakquorumdisks;however,theycanstillbeusedtobackupmetadata.19 IfsuitableexternalMDisksareavailable,theseMDisksareautomaticallyusedasquorumdisksthatdosupporttie-breaksituations.IfnosuitableexternalMDisksexist,theentiresystemmightbecomeunavailableifexactlyhalfthenodecanistersinthesystembecomeinaccessible(suchasduetohardwarefailureorbecomingdisconnectedfromthefabric).Insystemswithexactlytwocontrolenclosures,anuncontrolledshutdownofacontrolenclosuremightleadtotheentiresystembecomingunavailablebecausetwonodecanistersbecomeinaccessiblesimultaneously.Itisthereforevitalthatnodecanistersareshutdowninacontrolledwaywhenmaintenanceisrequired.Quorumconfigurationischosenbythefollowingcriteria:·Thedriveisredundantandstable.·Thedrivesareinacontrolenclosure.·Nounrecoverableerrorsareloggedagainstthedrive·Quorumisdistributedamongtheavailablecontrolenclosures.·Flashdrivesareavoided.·Nearlineharddiskdrivesareavoided.·Driveuseinorderofpriorityisspare,candidate,andthenmember.Thesecriteriaarenotrequirements.Onconfigurationswheremeetingallthecriteriaisnotpossible,quorumstillisautomaticallyconfigured.Itispossibletoassignquorumdiskstoalternativedrivesbyusingthechquorumcommand.However,youcannotmovequorumtoadrivethatcreatesalessoptimumconfiguration.Youcanoverridethedynamicquorumselectionbyusingtheoverrideyesoptionofthechquorumcommand.Thisoptionisnotadvised,however,unlessyouareworkingwithyoursupportcenter.Whenyouchangethemanageddisksthatareassignedasquorumcandidatedisks,followthesegeneralguidelines:·Whenyouusequorumdrives,usedrivesfromthecontrolenclosurewhenpossibleforthebestavailableperformanceandconnectivity.IfnoexternalMDisksareavailable,atleastonedriveandideallythreedrivesinthecontrolenclosuremustbepresentandhaveausethatisnotunusedorfailed.·WhenyouuseSAN-attachedquorumMDisks,aimtodistributethequorumcandidatediskssothateachMDiskisprovidedbyadifferent19 storagesystem.Forinformationaboutwhichstoragesystemsaresupportedforquorumdiskuse,refertothesupportedhardwarelist.·Beforeyouissuethechquorumcommand,ensurethestatusoftheMDiskordrivethatisbeingassignedasaquorumcandidatediskisreportedasonline.·UsesmallercapacityMDisks,orusedrivesasthequorumdevices,tosignificantlyreducetheamountoftimethatmightbeneededtorunarecoversystemprocedure(alsoknownasTier3orT3recovery),ifnecessary.5.1QuorumMDisksordrivesinHyperSwapsystemconfigurationsToprovideprotectionagainstfailuresthataffectanentirelocation(forexample,apowerfailure),youcanuseactive-activerelationshipswithaconfigurationthatsplitsasingleclusteredsystembetweentwophysicallocations.Formoreinformation,seeHyperSwap®configurationdetails.FordetailedguidanceaboutHyperSwapsystemconfigurationforhigh-availabilitypurposes,contactyourIBM®regionaladvancedtechnicalspecialist.IfyouconfigureaHyperSwapsystem,thesystemautomaticallyselectsquorumdisksthatareplacedineachofthethreesites.Thefollowingscenariosdescribeexamplesthatresultinchangestotheactivequorumdisk:·Scenario1:1.Site3iseitherpoweredofforconnectivitytothesiteisbroken.2.Iftopologyisstandard,thesystemselectsaquorumdiskcandidateatsite2tobecometheactivequorumdisk.IftopologyisHyperSwap,thesystemoperateswithoutanyactivequorumdisk.3.Site3iseitherpoweredonorconnectivitytothesiteisrestored.4.Assumingthatthesystemwascorrectlyconfiguredinitially,StorwizeV5000automaticallyrecoverstheconfigurationwhenthepowerisrestored.·Scenario2:1.Thestoragesystemthatishostingthepreferredquorumdiskatsite3isremovedfromtheconfiguration.19 1.Ifpossible,thesystemautomaticallyconfiguresanewquorumdiskcandidate.2.InHyperSwaptopology,thesystemselectsonlyanewquorumdiskthatisinsite3.Inastandardtopology,thesystemselectsaquorumdiskcandidateatsite1or2tobecometheactivequorumdisk.3.Anewstoragesystemisaddedtosite3.4.Instandardtopology,theStorwizeV5000administratormustreassignallthreequorumdiskstoensurethattheactivequorumdiskisnowatsite3again.InHyperSwaptopology,thesystemautomaticallyassignsthenewactivequorumdiskwhenthestoragesystemisinstalledandthesitesettingisconfigured.5.2IPquorumconfiguration窗体顶端窗体底端InsomeHyperSwap®configurations,IPquorumapplicationscanbeusedatthethirdsiteasanalternativetothird-sitequorumdisks.NoFibreChannelconnectivityatthethirdsiteisrequiredtouseanIPquorumapplicationasthequorumdevice.TheIPquorumapplicationisaJava™applicationthatrunsonahostatthethirdsite.TheIPnetworkisusedforcommunicationbetweentheIPquorumapplicationandnodecanistersinthesystem.Ifyoucurrentlyhaveathird-sitequorumdisk,youmustremovethethirdsitebeforeyouuseanIPquorumapplication.TherearestrictrequirementsontheIPnetworkandsomedisadvantageswithusingIPquorumapplications.Unlikequorumdisks,allIPquorumapplicationsmustbereconfiguredandredeployedtohostswhencertainaspectsofthesystemconfigurationchange.TheseaspectsincludeaddingorremovinganodecanisterfromthesystemorwhennodeserviceIPaddressesarechanged.OtherexamplesincludechangingthesystemcertificateorexperiencinganEthernetconnectivityissue.AnEthernetconnectivityissuepreventsanIPquorumapplicationfromaccessinganodethatisstillonline.IfanIPapplicationisoffline,theIPquorumapplicationmustbereconfiguredbecausethesystemconfigurationchanged.ToviewthestateofanIPquorumapplicationinthemanagementGUI,selectSettings>System>IPQuorum.YoucanalsousethelsquorumcommandtoviewthestateoftheIPquorumapplication.EvenwithIPquorumapplicationsatthethirdsite,quorumdisksatsiteoneandsitetwoarerequired,astheyareusedtostoremetadata.Quorum19 disksforeachsiteareselectedautomaticallyandcanbeconfiguredinthemanagementGUI,byselectingPools>MDisksbyPools.YoucanalsousethechquorumcommandtoassignMDiskasaquorumdisk.AnIPquorumapplicationcanalsoactasthequorumdeviceforsystemsthatareconfiguredwithastandardtopologythatdonothaveanyexternalstorageconfigured.Thisconfigurationgivesasystemtie-breakcapability,automaticallyresumingI/Oprocessingifhalfofthesystem"snodecanistersareinaccessible.ThemaximumnumberofIPquorumapplicationsthatcanbedeployedisfive.Applicationscanbedeployedonmultiplehoststoprovideredundancy.5.3IPquorumrequirementsForstablequorumresolutions,anIPnetworkmustprovidethefollowingrequirements:·ConnectivityfromtheserversthatarerunninganIPquorumapplicationtotheserviceIPaddressesofallnodecanisters.ThenetworkmustalsodealwithpossiblesecurityimplicationsofexposingtheserviceIPaddresses,asthisconnectivitycanalsobeusedtoaccesstheserviceassistantinterfaceiftheIPnetworksecurityisconfiguredincorrectly.·Port1260isusedbyIPquorumapplicationstocommunicatefromthehoststoallnodecanisters.·Themaximumround-tripdelaymustnotexceed80milliseconds(ms),whichmeans40mseachdirection.·Aminimumbandwidthof2megabytespersecondisguaranteedfornodecanister-to-quorumtraffic.ThefollowingminimumrequirementsmustbemetonthehoststhatareusedtorunIPquorumapplications:·Supportedoperatingsystems:oRedHatEnterpriseLinux6.5,RedHatEnterpriseLinux7oSUSELinuxEnterpriseServer11m3,SUSELinuxEnterpriseServer12·SupportedJavaRuntimeEnvironments:IBM®Java7.1,IBMJava819 5.4InstallingIPquorumIfyouchangetheconfigurationbyaddinganenclosure,changingaserviceIPaddress,orchangingSSLcertificates,youmustdownloadandinstalltheIPquorumapplicationagain.TodownloadandinstalltheIPquorumapplication,completethefollowingsteps:1.InthemanagementGUI,selectSettings>System>IPQuorumandclickeitherDownloadIPv4ApplicationorDownloadIPv6ApplicationtocreatetheIPquorumJavaapplication.Youcanalsousethecommand-lineinterface(CLI)toenterthemkquorumappcommandtogenerateanIPquorumJavaapplication.Theapplicationisstoredinthedumpsdirectoryofthesystemwiththefilenameip_quorum.jar.2.TransfertheIPquorumapplicationfromthesystemtoadirectoryonthehostthatistoruntheIPquorumapplication.3.UsethepingcommandonthehosttoverifythatitcanestablishaconnectionwiththeserviceIPaddressofeachnodecanisterinthesystem.4.Onthehost,usethecommandjava-jarip_quorum.jartoinitializetheIPquorumapplication.5.ToverifythattheIPquorumapplicationisinstalledandactive,selectSettings>System>IPQuorum.ThesystemautomaticallyselectsMDisksforquorumdisks.InaHyperSwapconfigurationwithIPquorum,thesystemautomaticallyselectsanMDiskfrombothsites.TheseMDisksstoremetadatathatareusedforsystemrecovery.IfyouwanttoselectspecificMDisktouseasquorumdisks,selectMDiskbyPoolsandright-clicktheMDiskandselectQuorum>ModifyQuorumDisk.ThenewIPquorumapplicationisdisplayedinthetableofdetectedapplications.YoucanalsousethelsquorumcommandonthesystemCLItoverifythattheIPquorumapplicationisconnectedandistheactivequorumdevice.IfyouwanttomodifytheMDiskthatareusedforquorumbyusingthecommand-lineinterface,usethechquorumcommand.Parenttopic:Quorumdisk19 5.4ManualquorumdiskoverrideinaHyperSwapsystem窗体顶端窗体底端Amanualquorumdiskoverrideisrequiredwhenyouexperiencearollingdisaster.Inraresituations,thesystemissubjecttowhatisreferredtoasarollingdisaster.Arollingdisasteroccurswhenanincidenthaswidescope,anditseffectsarefeltinmultiplestepsoveranextendedtimeperiod.Thefollowingexamplescenariodescribesarollingdisasterandshowshowtorecoverfromthatrollingdisaster.Anexampleofarollingdisasteroccurswhenthefollowingsituationistrue:1.Thelinkbetweenthetwositesfails,atwhichpointonesiteusestheautomaticquorumfeaturetocontinueoperation.2.Thesystemsitethathascontrolofthequorumdiskfails(duetoapoweroutage,forexample).ThisexampleleavesthesecondsiteastheonlysitethatispotentiallycapableofcontinuingdataI/O.However,itisunabletodosountilitgainscontrolofthequorumdisk.TheMDisksinthesecondsitestop.Nodesatthesitedisplaythenodeerror551,indicatingthataninsufficientnumberofnodesareavailabletoformaquoruminaHyperSwap®systemconfiguration.Inthisscenario,youcanrunthesataskoverridequorumcommandtooverridetheautomaticquorumdiskselectionandcreateanewsystemthatcontainsthenodesinthesecondsite.Note:Ifafabricdisruptionoccurswhilethesataskoverridequorumcommandisrunning,itispossiblethatasubsetofthenodeswillupdatetheircluster(system)ID.Theupdatednodesdisplaythenodeerror550;thenodesthatwerenotupdateddisplay551andthenodesareassignedtotwodifferentsystems.Inthissituation,youcanrunthesataskoverridequorumcommandagainononeofthenodesthatreportedtheerror551.Thiscommandupdatesallthenodesinthetwosystemswithanewcluster(system)ID.Youcanthenrecoverdata.5.5EnforcingconditionsforaquorumYoumustrunthechsystem-topologyhyperswapcommandaspartoftheinstallationprocessforthesystemtomakethesataskoverridequorumcommandavailableifarollingdisasteroccurs.Thesataskoverridequorum19 commandisnotavailableinsystemsthatdonothavethetopologysettohyperswap.Beforeyoucanusethecommand,thefollowingprerequisitesmustbemet:·AllI/Ogroupswithtwonodesareassignedwithonenodeinsite1andtheotherinsite2.·AllstoragesystemswithMDisksmusthavetheirsitedefined.Whentheseprerequisitesaremetandautomaticquorumselectionisenabled,thesystemattemptstoassignonequorumdiskwithinallthreesites.IfasitedoesnothaveanMDisksuitabletobeaquorumdisk,aquorumdiskisnotassignedtoit.Note:Afterthechsystem-topologyhyperswapcommandisrun,youcannotalterthesiteassignmentofanycontrollerexceptwherethatcontrollerisanewcontrollerthathasonlyunmanagedMDisks.Itwillalsonotallowsitesettingsfornodes.Thisenforcementisrequiredtoensurethatthesystemoperatescorrectlytoallowthesataskoverridequorumcommandtooperatecorrectly.Whenyourunthechsystem-topologystandardcommand,itagainispossibletoalterthesitesettingsfornodesandcontrollers.However,thiscommanddisablestheoverridequorumfeature.Therefore,aimtorunchsystem-topologyhyperswapwhenyoucompleteyourchangestoreenablethissupport.六、HyperSwapconfigurationwithoutusinginterswitchlinks窗体顶端窗体底端ThemostsimpleIBM®HyperSwap®configurationisbuiltbyattachingeachcontrolenclosuredirectlytotheFibreChannelswitchesinthelocalandtheremoteproductionsite.Thisconfigurationisdonewithoutusinginterswitchlinks(ISLs).6.1HyperSwapconfigurationruleswithoutusingISLsThefollowingrulesmustbeobservedwhenyouconfigureaHyperSwapsystemwithoutusingISLs:19 ·Foreverystoragesystem,createonezonethatcontainsStorwize®V5000portsfromeverynodeandallstoragesystemports,unlessthezoningguidelinesforthatstoragesystemstatedifferently.However,donotconnectastoragesysteminonesitedirectlytoaswitchfabricintheothersite.Instead,connecteachstoragesystemonlytoswitchedfabricsinthelocalsite.Important:AllSASexpansionenclosuresinaFlashSystem™V9000systemmustbezonedtoallcontrolenclosuresinbothsites.·EachStorwizeV5000nodemusthavetwodirectFibreChannelconnectionstooneormoreSANfabricsatbothlocationsthatcontainStorwizeV5000nodes.·YoucanincludepoweredcomponentsbetweenStorwizeV5000andtheswitchesinaHyperSwapsystemconfiguration.Forexample,youcanusepowereddensewavelengthdivisionmultiplexing(DWDM)FibreChannelextenders.·BepreparedtoprovideandreplacelongwaveSFPtransceiversincasetheyfail.·Someserviceactionsrequiretheabilitytodoactionsonthefrontpanelorthroughthetechnicianportofallnodesinasystemwithinashort-timewindow.IfyouuseHyperSwapsystems,youarerequiredtoassistthesupportengineerandprovidecommunicationtechnologytocoordinatetheseactionsbetweenthesites.ConfiguretheHyperSwapsystemthatdoesnotincludeinterswitchlinks(ISLs)accordingtothefollowingrules:·TheminimalSANconfigurationconsistsofoneFibreChannelswitchperproductionsiteastwoseparatefabrics.Forhighestreliability,usetwoswitchesperproductionsite.SinglefabricconfigurationsarenotsupportedforHyperSwapI/Ogroupsystems.Note:FCIPconnectivityisnotsupportedbetweennodeswhenaHyperSwapsystemisconfiguredwithoutusingISLs.FCIP(oranyFibreChannelextenderorSANrouterthatissupportedforintersystemcommunications)mightbeusedintheconnectiontothequorumdiskatthethirdsite.FCIPconnectivityissupported(oranyFibreChannelextenderorSANrouterthatissupportedforintersystemcommunications)bothbetweennodesattwodifferentsitesandbetweennodesandthequorumdiskatthethirdsitewhenaHyperSwapsystemisconfiguredwithISLs.19 ·AswitheveryStorwizeV5000clusteredsystem,youcanuseISLsforhost-to-node(withuptothreehops)orfornode-to-storage(atmostonehop)access.However,configuretheSANzonessothatISLsarenotusedinpathsbetweenStorwizeV5000nodes.·Inasystemwithfourportspernode,attachhalfoftheportsofeachnodetotheFibreChannelswitchesintheproductionsitewherethenodeislocated.·Inthesamesystemwithfourportspernode,attachtheremaininghalfoftheportsofeachnodetotheFibreChannelswitchesintheother(remote)productionsite.·ConnecteachstoragesystemattheproductionsitestoFibreChannelswitchesinthesitewherethestoragesystemislocated.·ConnectthestoragesystemwiththeactivequorumdiskstoFibreChannelswitchesinbothproductionsites.·ToavoidfabrictopologychangesincaseofIPerrors,itisagoodpracticetoconfigureFCIPlinkssothattheydonotcarryISLs.Note:ThisguidelineappliesonlyifFCIPisusedtoconnecttoaswitchatthethirdsitewherethequorumdiskislocated.Restriction:Donotconnectastoragesysteminonesitedirectlytoaswitchfabricintheothersite.ConnectivitybetweenStorwizeV5000portsatonesitetostorageattheothersitethatusesISLstotravelbetweenthelocationsarenotaffectedbythisrestriction.Itisstrictlyrequiredthatthelinksfrombothproductionsitestothequorumsiteareindependentanddonotshareanylong-distanceequipment.19'