NexentaStor & NexentaFusion Unified Block & File … is the industry’s leading software-defined...

Copyright©2017NexentaSystems,ALLRIGHTSRESERVEDwww.nexenta.com

NexentaStor&NexentaFusionUnifiedBlock&FileSoftware-DefinedStorage

ProductGuideNovember2017

NexentaStorProductGuide

2 Copyright©2017NexentaSystems,ALLRIGHTSRESERVEDwww.nexenta.com

TableofContents

1 NexentaStorOverview......................................................................................................51.1 IntroductiontoNexentaStorSDS..............................................................................................................................51.2 NexentaStorSoftwareArchitecture.......................................................................................................................71.3 NexentaStorHighAvailability................................................................................................................................101.4 NexentaStorReferenceArchitectureandAppliances..................................................................................111.5 NexentaStorLicensing..............................................................................................................................................121.6 BenefitsofNexentaStorSoftware-DefinedStorage......................................................................................141.7 WheretoFindMoreInformation.........................................................................................................................152 DeploymentScenarios&UseCases.................................................................................162.1 UseCases.........................................................................................................................................................................162.2 DeploymentScenarios...............................................................................................................................................172.3 VMwareIntegration...................................................................................................................................................182.4 OpenStackIntegration..............................................................................................................................................182.5 StretchClustersandMetroHAConfigurations...............................................................................................19

3 UnifiedBlockandFileServices........................................................................................203.1 StoragePoolingArchitecture.................................................................................................................................203.2 PerformanceManagement......................................................................................................................................213.3 DeviceFailureHandling...........................................................................................................................................223.4 DataatRestEncryption............................................................................................................................................233.5 FileSystemsandSharedFileServices................................................................................................................233.5.1 SharedFileServices..................................................................................................................................................243.5.2 AccessControlLists..................................................................................................................................................243.5.3 Quotas,ReservationsandCapacityManagement.......................................................................................243.5.4 StorageQoSForFileServices...............................................................................................................................25

3.6 VolumesandSharedBlockServices....................................................................................................................263.6.1 VolumeGroups...........................................................................................................................................................263.6.2 iSCSIBlockServices..................................................................................................................................................263.6.3 FibreChannelBlockServices...............................................................................................................................27



4 NexentaStorDataProtection..........................................................................................284.1 InstantSpaceOptimizedSnapshotsandClones............................................................................................284.2 SnapshotServices........................................................................................................................................................294.3 HighPerformanceReplicationOverview..........................................................................................................294.4 LicensingConsiderationsforHPR........................................................................................................................304.5 ScheduledReplicationServices.............................................................................................................................314.6 ContinuousReplicationServices..........................................................................................................................324.7 Multi-Destination........................................................................................................................................................334.8 MovingDatasetToandFrom3rdPartyOpenZFSSystems........................................................................33



PrefaceCopyright,Trademarks,andComplianceCopyright©2017NexentaSystems™,ALLRIGHTSRESERVED

Notice:Nopartofthispublicationmaybereproducedortransmittedinanyformorbyanymeans,electronicormechanical,includingphotocopyingandrecording,orstoredinadatabaseorretrievalsystemforanypurposewithouttheexpresswrittenpermissionofNexentaSystems(hereinafterreferredtoas“Nexenta”).

Nexentareservestherighttomakechangestothisdocumentatanytimewithoutnoticeandassumesnoresponsibilityforitsuse.NexentaproductsandservicesonlycanbeorderedunderthetermsandconditionsofNexentaSystems’applicableagreements.Allofthefeaturesdescribedinthisdocumentmaynotbeavailablecurrently.RefertothelatestproductannouncementorcontactyourlocalNexentaSystemssalesofficeforinformationonfeatureandproductavailability.Thisdocumentincludesthelatestinformationavailableatthetimeofpublication.

Nexenta,NexentaStor,NexentaEdge,andNexentaConnectareregisteredtrademarksofNexentaSystemsintheUnitedStatesandothercountries.Allothertrademarks,servicemarks,andcompanynamesinthisdocumentarepropertiesoftheirrespectiveowners.



1 NexentaStorOverview

NexentaStoristheindustry’sleadingsoftware-definedstorage(SDS)platform,deliveringfull-featured,enterprise-classunifiedblockandfilestorageservices.Asofversion5,NexentaStorisusedbythousandsofcustomersinconfigurationsrangingfromtensofterabytestomultiplepetabytesasareplacementforlegacystorageareanetwork(SAN)andnetworkattachedstorage(NAS)hardwareappliances.

Unlikehardwareappliancesfromtraditionalstoragevendors,NexentaStorisdeliveredassoftwarethatcaneitherbedeployedonbaremetalindustry-standardx86serversconnectedtosharedSASstorageenclosuresanddevices,orasavirtualmachineonawidevarietyofhypervisorsonpremiseorinpublicclouds.NexentaStor5incorporatesastateoftheartmanagementframeworkexposinganexhaustivesetofdeveloperfriendly,self-documentingRESTAPIsthatarethefoundationforallusermanagementinterfaces(CLIandGUI)andecosystemplugins.NexentaFusionshipswithNexentaStor5andprovidesasinglepaneofglassmanagementinterfaceformulti-systemdeployments.

Beingdeliveredassoftwareonlygivescustomersnewlevelsofflexibilityandperformance,eliminateshardwarelock-in,significantlyreducesstoragecosts,andgenerallysimplifiesstoragemanagementandscaling.

1.1 IntroductiontoNexentaStorSDSNexentaStorprovidesstandardfile(NFSandSMB)aswellasblock(FCandiSCSI)protocolservices.Thesoftwareisdeployedasafullstorageoperatingsystemonstandardx86baremetalservers,orinvirtualmachinesinprivateorpubliccloud.NexentaStorcanberuninsingle-nodeconfigurationsoninternaldevicesorindual-nodehigh-availability(HA)clusterconfigurations,withSAS-connectedsharedbackenddevices.

Figure1-1: NexentaStorAppliancesConfiguration



NexentaStorbuildsontheopensourceOpenZFSfilesystemtodeliverhigh-performance,enterprise-classdataservicesthateffectivelycompeteandwinagainstlegacystorageappliancevendors:

Figure1-2:NexentaStor5FeatureSupport

Protocols File:NFSv3,NFSv4,SMB1.0,SMB2.1,SMB3Block:FibreChannel,iSCSI

Configurations Singlenode–x86baremetalDual-nodeHighAvailabilityclusters–x86baremetalMetroHAStretchedclusters–x86baremetalVirtualStorageAppliance–VMwareESXi,KVMAmazonWebServices

DataManagement All-Flash,Hybrid,orAll-DiskpoolsRAID10,N+1,N+2,N+3OpenZFSend-to-enddataintegrityUnlimitedsnapshots&clonesUnlimitedfilesystemsizeHighperformanceinlinedatareductionThinprovisioningStorageQualityofServiceSnapshotbasedScheduledReplicationContinuousAsynchronousReplication

Management SelfdocumentingRESTAPI,CLI,SNMPNexentaFusion(HTML5based)

ClientOSSupport VMwareESXi,MicrosoftWindows,CentOS,RHEL,Ubuntu

EcosystemIntegration SMB3ODXforMicrosoftHyper-VVMwareVAAIBlockVMwareVirtualVolume(VVOL)2.0VMwarevCenterPluginVMwareSiteRecoveryManagerOpenStackCinder&ManilaDockerVolumePluginKubernetesPersistentVolume



ThismaturesetoffeatureshasallowedNexentatosuccessfullysellintoawidevarietyofmarketverticalsandusecases,fromhigh-performancelow-latencyall-flasharrayssupportingvirtualenvironmentsandbusiness-criticalapplications,allthewaytolarge-scalecost-optimizedbackupandarchiverepositories.

ThetypesofconfigurationsandtargetusecasesforNexentaStorareshowbelow:

Figure1-3: NexentaStorUseCases

Theabilitytoselecttherighthardwareconfigurationfortherightworkloadgivescustomersmaximumflexibility.Havingthesamesoftwarestackrunningonhigh-performanceall-flash,balancedhybridandcost-optimizedbackupandarchivesetupssimplifiesdatamovementacrosstiersandmanagementofthefullstorageinfrastructure.

1.2 NexentaStorSoftwareArchitectureNexentaStor5buildsontheopensourceOpenZFSfilesystemforitscoredataservicesandcomplementsitwithhighperformanceblockandfileservices,high-availabilityclustering,kernelbasedmulti-sitereplicationandtheNexentaManagementFramework(NMF).

Asshowninthefigurebelow,NMFprovidesatightcoverontheunderlyingstorageoperatingsystemandhandlesallprovisioningandmanagementoperations.Fromauserperspective,NMFpresentsanexhaustiveself-documentingRESTAPIthatprovidesaconsistentfoundationforthesystem’sCommandLineInterface(CLI),theNexentaFusiongraphicaluserinterfaceandallsupportedecosystemplugins.



Figure1-4: NexentaStorHighLevelArchitecture

NexentaStor5benefitsfromallthescalability,performance,andreliabilityimprovementsinthecoreplatformthatwereimplementedoverthelastfewyearsinNexentaStor4.NexentaStor5alsoincorporatesanumberofnewandenhanceddevicedrivers,addingsupportfor25Gb/sand40Gb/sEthernetinterfaces,aswellas32Gb/sFibreChannelHBAs.

TheNexentaManagementFrameworkwasfirstintroducedwithNexentaStor5.0andfullyreplacedthelegacyNexentaManagementServer(NMS),NexentaManagementConsole(NMC),andNexentaManagementView(NMV)thatwerepartofNexentaStor4.xandallpreviousreleases.

Bydesign,NMFisahigh-performance,multi-threaded,fault-tolerantmanagementplanethatprovidesastreamlinedandsimplifiedstorage-centricmanagementexperience.BuildingtheNexentaStorCLIaswellasallmanagementproductsontopoftheNMFRESTAPIensuresthatalloperationsandallstatisticsavailablethroughtheCLIandGUIaresupportedviatheRESTAPI.



TheNexentaStorRESTAPIisself-documentingandprovidesaninteractiveSwaggeruserinterfacefordevelopersandtechnologypartnerslookingtobuildstorageautomationandorchestration.

Figure1-5: NexentaStorRESTAPIManagementScreen

DaytodaymanagementoperationsareaccomplishedusingtheNexentaFusionmanagementserver,freelyavailablewithanyNexentaStor5license.NexentaFusioncomplementsanyNexentaStor5deploymentandprovidesasinglepaneofglassGraphicalUserInterfaceformultipleNexentaStorappliances.NexentaFusionisavailableasaVMwareOVAandasaDockercontainerforsimpledeploymentonanyLinuxhost,physicalorvirtual.Itincorporatesintuitiveworkflowsforallprovisioningandfaultmanagementtasksanddeliversadvancedanalyticsdashboardsfordetailedmonitoringandtroubleshooting,storinguptotwoyearsofhistoricalservicedata.

Figure1-6: NexentaFusionManagementScreen



1.3 NexentaStorHighAvailabilityNexentaStorhighavailability(HA)allowsyoutoconfiguretwoNexentaStornodestoprovideredundantaccesstostoragepools.Active-passive(twoNexentaStornodes,onepool)andactive-active(twonodes,twopoolsormore)configurationsaresupported.Ifanodeisunabletodeliverstorageservicesforsomereason,theothernodeautomaticallytakesover.

Technically,aNexentaStorHAconfigurationconsistsofanHAclusterwhereoneormoreHAservicesarerunning:

• AnHAclusterisapairofNexentaStornodesthatshareaccesstobackendstoragedevices,havenetworkconnectivitytoeachother,andonwhichthehighavailabilityfeatureisenabled.

• AnHAservicespecifiestheVirtualIP(VIP)address(es)orFibreChannelportsfortheHAcluster,thestoragepool(s)tobeprotected,andwhichofthenodesinitiallyprovidesclientsaccesstothestorage.

TofacilitateHAconfigurationforfileandiSCSIservices,eachnodeshouldhaveatleastonestaticIPaddressassignedtoit,andeachVIPshouldhaveitsownstaticIPaddress.

Figure1-7:ExampleNexentaStorHighAvailabilityConfiguration

Inthisexample,Node-AandNode-BcompriseanHAcluster.Therearetwostoragepools,Pool-AandPool-B,thatconsistofbackendstoragedevicesthatareaccessibletobothnodesintheHAcluster.TherearetwoHAservicesinthisconfiguration:onethatprovidesaccesstoPool-AusingVIP-AandanotherthatprovidesaccesstoPool-BusingVIP-B.Inthisexample,Node-AservesasthebackupforPool-B,andNode-BservesasthebackupforPool-A.

Node-AandNode-Bexchangestatusinformationusinganumberofdifferentnetworkandstorageheartbeatmechanisms.Ifalloftheheartbeatmechanismsaredisruptedforagivenlengthoftime,thenthemainnodeisconsideredtohavefailed,andthebackupnodetakesover.Inthisexample,failureofNode-AwouldleadtoNode-BtakingoverPool-AandVIP-A,andfailureofNode-BwouldleadtoNode-AtakingoverPool-BandVIP-B.

Oncethefailednodeisrestored,itcantakebackitsstoragepool.Youcanconfigurethistooccurautomaticallywhenthenodecomesbackonline,oryoucandothismanually.



1.4 NexentaStorReferenceArchitectureandAppliancesWhilethematurity,flexibilityandcost-effectivenessofNexentaStorsoftware-definedstoragemakeitattractiveforabroadsetofEnterpriseusecases,meetingtheneedsofEnterprisecustomersalsorequiresspecificattentiontodeploymentandsupportability.

Enterprisecustomersgenerallyexpecttohave“onethroattochoke”whenitcomestosoftwareandhardwaresupport.ThisiswhyNexentaworkscloselywithhardwarepartnersandserverOEMstocertifyfullstackReferenceArchitectures(RAs)thataddressall-flash,hybridandall-diskstoragerequirementsandscalefromtensofterabytestomulti-petabyteappliances.

Figure1-8: ReferenceArchitectureExamples

Theseend-to-endsolutionsaredeliveredthroughserverpartnerssuchasCisco,DellEMC,Ericsson,LenovoorSupermicrowithmanyprovidingfullstacksupport,takingfirstcallonbothsoftwareandhardwareandprovidingaseamlesssupportexperiencetoNexentaStorusers.

Inadditiontoreferencearchitectures,aselectsetofserverOEMsofferNexentaStorbasedhardwareapplianceswherethesoftwareispre-loadedandpre-configuredinmanufacturingprovidingaturn-keyhardwareapplianceexperiencetoendcustomers.

Certifyingareferencearchitectureentailsthefollowing:

• WorkingwiththehardwarepartnertocreateNexentaskusforthespecifichardwareconfigurations,explicitlyspecifyingCPU,DRAM,HBAandNICcomponentsandfirmware,todelivertherightperformanceandcapacityscaling

• Performingextensivehardwareandsoftwareinteroperabilitytestingtoensurethatthesolutionwilloperateandperformasexpectedinproductionenvironments

• DevelopinghardwarespecificchassismanagementpluginsforNexentaStorandNexentaFusiontosimplifyday-to-dayoperationsrelatedtohardwaremanagement,devicereplacement,etc.



Figure1-9: NexentaFusionChassisManagementforSupermicroAppliance

FormoredetailsonNexentaStor5referencearchitecturesandappliances,pleaseseetheNexentaStor5HardwareCompatibilityList.

1.5 NexentaStorLicensingNexentaStor5isavailableasanEnterpriseEditionorCommunityEdition:

• NexentaStorEnterpriseEditionissoldasaperpetualsoftwarelicensebasedonrawcapacityundermanagement(measuredinTB).Supportandservicesaresoldseparately.Pricingistieredontheamountofrawcapacityrequiredforasystem,withalargerconfigurationgettingalowerpriceperGBthanasmallerone.

TheEnterpriseEditionincludesallcorestoragefunctionalitysuchassnapshots,clones,inlinedatareduction,softwareRAIDandsnapshotbasedscheduledreplication.ItalsoincludestherighttouseNexentaFusionastheGraphicalUserInterfaceforthesystemrunningthatlicense.Additionaloptionsaresoldonaper-nodebasisandincludefeaturessuchasHigh-AvailabilityCluster,MetroHA,ContinuousReplicationorFibreChannelsupport.

• NexentaStorCommunityEditionisalimited-functionality,limited-capacity,freeversionofthesoftwarethatcanbeusedfornon-productiondeployments.OutsideoftheonlineNexentaCommunityforums,nosupportservicesareavailableforNexentaStorCommunityEdition.ANexentaFusionservercanmanageatmostoneNexentaStorCommunityEditionappliance.Formoredetails,seetheonlineNexentaCommunityforums.



Figure1-10:NexentaStorSoftwareLicenses

LicenseType TimeLimit CapacityLimit SeparatelyLicensedOptions

EnterpriseEdition None Variable • HighAvailability Cluster• HPRContinuousReplication• FibreChannelTarget• MetroHA

Trial 45days Variable TrialperiodincludesEnterpriseEditionoptionalfeatures

CommunityEdition None 10TBAllocated None

NexentaStor5implementsasimplelicensingenginethatseamlesslyintegrateswiththenewcustomerlicenseportalsonNexenta.com.ActivatingalicenseonaNexentaStor5appliance(singlenodeorHAcluster)isassimpleasenteringtheactivationtokenprovidedbythecustomerlicenseportalandlettingthesystemautomaticallyregisteranddownloadalicensefile.

ThefollowingfeaturescanbeaddedtoanEnterpriseEditionlicense:

• High-AvailabilityCluster–ConfiguresapairofphysicalserverstorunasahighlyavailableNexentaStorappliance,providingredundantaccesstosharedstoragepools.IfoneoftheNexentaStornodesshouldfail,allstorageservicesareseamlesslyfailedovertotheothernode.Seesection1.3formoredetails.

• ContinuousReplication–TheEnterpriseEditionlicenseincludesscheduledreplicationservicestoaremoteappliance,withaminimumscheduleofareplicatedsnapshotevery15minutes.TheContinuousReplicationoptionallowsscheduledreplicationasoftenaseveryminute.ThisoptionalsounlocksthecontinuousasynchronousreplicationfunctionalitythatallowsasclosetozeroRecoveryPointObjective(RPO)aspossibleoveranydistance,withoutaffectingapplicationperformance.Seesection4.6formoredetails.

• FibreChannelfunctionality–AllowsyoutoconfigureFCtargetsontheapplianceandserveLUNsoverFibreChannel.

• MetroHA–EnablesNexentaStortodeliverzeroRPOcontinuousavailabilitydisasterrecoverybetweensitesinthesamemetroarea.Seesection2.5formoredetails.

ContactNexentaSystemsforinformationonpurchasingalicenseforthesoftwareandindividualfeatures.



1.6 BenefitsofNexentaStorSoftware-DefinedStorageWithitsperformance,enterprise-gradereliabilityandfeatureset,NexentaStorisuniqueinthemarketinitsabilitytobringtheflexibility,agilityandcostsavingbenefitsofSoftware-DefinedStoragetotraditionalenterprisestorageenvironments.

Morespecifically,NexentaStordeliversthefollowingbenefits:

• Nocompromise.NexentaStorincludesalltheadvancedstoragefunctionalitythatcanbeexpectedofhigh-end,enterprise-classstoragearrayssupportingunifiedblockandfileservices.Thesolutionalsosupportshighlydifferentiatedfeaturessuchashigh-performanceinlinedatareductionforall-flashconfigurations,tripleparityRAIDforlargearchivesetups,continuousreplicationfornearzeroRPOdisasterrecoveryscenarios,andunlimitedfilesystemsizes.

• Greatperformance.NexentaStorreferencearchitecturesmakeuseofthelatesthardwarecomponentsandgenerallytakeadvantageoflargeramountsofDRAMintheNexentaStornodesthanistypicallyfoundintraditionalstorageappliances.Thecombinationofhigh-performancesoftwareandhigher-performancehardwarecomponentsintheNexentaStorreferencearchitecturestranslatesintosolutionsthatgenerallyoutperformthecompetition.

• Totalcontrol.CustomersrunningNexentaStorsolutionseffectivelyareinfullcontrolofwhattodeployfortheirstorageneedsandwhentorefreshtheirstorageinfrastructure.Ratherthanhavingatraditionalstorageappliancevendordictatewhenaparticulararrayneedstobereplaced,NexentaStorcustomersgettochoosewhentorefreshthestandardx86servercomponentssupportingtheirstorageinfrastructure.HavingtheoptiontorunaNexentaStorapplianceforfiveorevensevenyearsonthesamehardwarecantranslateintosignificantcostsavingsoverthelifeofasystem.

• Simplifiedmanagementandscaling.NexentaStor5implementsadeveloper-friendly,self-documentedRESTAPIforeaseofautomationandorchestration.Formoretraditionaloperationalenvironments,NexentaFusiondeliversamodernandintuitivegraphicaluserinterface(GUI)forallprovisioningandmonitoringworkflows.

• Lowertotalcostofownership.Byrunningonstandardx86servers,NexentaStorallowscustomerstoacquirehigh-performance,enterprise-gradestoragesolutionsatindustry-standardx86serverprices,avoidingthetypicalhighmarginchargedbytraditionalstorageappliancevendors.Furthermore,NexentaStor’sperpetualsoftwarelicensesallowcustomerstosimplyrepurposelicensesandsaveoverthelongrunashardwarerefreshesonlyincurhardwarecosts,notsoftwarecosts.



1.7 WheretoFindMoreInformation

Document Purpose

QuickStartGuides ThesedocumentsprovidebasicinformationaboutessentialfunctionalityofNexentaStorandconciseprocedurestogetyouupandrunningasquicklyaspossible.

Thequickstartguidescoverthefollowingtopics:• NexentaStorandNexentaFusioninstallation• NexentaStorCLIConfiguration• NexentaStorCLIReferenceGuide• NexentaStorHighAvailability• NexentaStorHighPerformanceReplication• NexentaStorRESTAPI• NexentaStorData-at-RestEncryption• NexentaStorvCenterplugin• NexentaStorVVOLAdministration

NexentaStorCLImanualpages Enter<command> -h forhighlevelinformationonsub-commandsandoptionsandman <command> togetdetailedusageinstructions

NexentaFusiondocumentation NexentaFusion’sonlinehelpprovidesstep-by-stepproceduresforcommonconfigurationandmonitoringtasks.

Additionaldocumentation:• NexentaFusioninstallation• NexentaFusionUserGuide

Releasenotes High-leveloverviewofnewfunctionalityinagivenreleaseanddetailedreviewofresolvedandknownissues.

TheNexentaStorquickstartguidesandNexentaFusiondocumentationareavailableonlineinPDFandHTMLformatfromnexenta.comat:https://nexenta.com/products/documentation



2 DeploymentScenarios&UseCases

2.1 UseCasesNexentaStorsoftwareissuccessfullyusedbythousandsofcustomersoverawiderangeofusecases,fromhighperformancetransactionaldatabasestoprivatecloudandcost-optimizedverylarge-scalebackupandarchive.Theabilitytousethesamestoragesoftware,withthesamerichfeaturesetandmanagementinterfacesandAPIsacrossalltheseworkloadsenablescustomerstomassivelysimplifytheirstorageinfrastructure.

Figure2-1:TypicalNexentaStorUseCases

All-flashconfigurationsareidealforhighperformanceapplications,databasesandcloudhostingusecases.NexentaStoronall-SSDconfigurationsprovideshighperformance,lowlatencystorageservices.All-flashNexentaStorreferencearchitecturecanhitverylow$/GBpricepointsthatmakeall-flashstoragecost-effectiveforalargershareofapplications.Combiningthelowcapexofsoftware-definedonall-flash(builtonindustrystandardx86serversandSSDs)withthelowopexbenefitsofall-flashstorageingeneral(easiertorun,morereliable,lesspower,lessspace)hasallowedanumberofNexentacustomerstofullystandardizeonall-flashsystems,deployingmultiplepetabytesofall-flashNexentaStorforbothblockandfileservices.

HybridconfigurationscombineafewSSDsforwriteloggingandreadcachingwithNL-SASHDDsforlong-termdatastorage.Theseconfigurationsarepopularforprivatecloudandthewidevarietyofapplicationsrequiringunstructureddatastorage,NASservicesandfull-featuredNFSandSMBservices.Theseconfigurationsoftenscalefromhundredsofterabytestopetabyteswithsingleordualparityraidtooptimallybalancecostandperformancerequirements.

All-Diskconfigurationsareidealforlowcostbackupandarchiveusecases.Dependingonthebackupsoftwareused,customersleverageNexentaStorFibreChannel,iSCSI,NFSorSMBservices.Inthisusecases,systemsscaletomulti-petabytes,withlarge10TBor12TBHDDsandtripleparityraid.Tofurthersimplifydatamanagement,fewverylargefilesystemsaregenerallyconfigured,fromhundredsofTBtosingledigitPBscale.NexentaStorbuilt-inOpenZFSdataintegrityprotectionmechanismsensurethatfaithfullong-termdataretentionandthesoftware’sadvancedremotereplicationfunctionalitycanbeusedformulti-sitedisasterrecoveryconfigurations.



2.2 DeploymentScenariosANexentaStor5appliancebyitselfcanbemanagedviaCLIorRESTAPIs.TomanagetheapplianceviaGUI,itmustberegisteredonaseparateNexentaFusionserver,withaVMwarevCenterplugin,orboth.

AtypicalcustomerdeploymentincludesoneormoreNexentaStorappliancesmanagedbyasingleNexentaFusionserver,providingasingle-pane-of-glassGUI,asshownbelow.NotethattheNexentaFusionservermustbedeployedonadedicatedLinuxhost,oradedicatedLinuxvirtualmachine.

Figure2-2: NexentaStor5DeploymentScenarios

ForVMwareenvironments,NexentaStor5baremetalappliancescanbeusedtoprovidehigh-performanceFC,iSCSI,orNFSdatastorestovSphere.NexentaStor5canalsobedeployedasvirtualappliances,inVMwarevirtualmachines.BothbaremetalandvirtualizedNexentaStor5deploymentscanbefullymanagedviatheNexentaStor5vCenterplugin.

ThedeploymentscenariodepictedontherighthandsideofFigure2-2isafastgrowingusecaseforNexentaStorSDSinscenariosthatrequiretrueenterpriseclassfileservicesonhyper-convergedinfrastructure(e.g.NutanixorVMwarevSAN)andinenvironmentsrequiringadvancedmulti-tenantfileservices.Inthese,NexentaStorSDSissimplydeployedinvirtualmachines,consumingvmdksforbackendstorage.ManagementcanbeorchestratedthroughtheNMFRESTAPIs,CLI,orthroughthevCenterpluginwhichisitselfmulti-tenantcapable.



2.3 VMwareIntegrationEcosystemintegrationisanimportantbenefitofNexentaStorportfolio.NexentaStor5supportsVAAIforblockservices,andcomeswithanewVMwarevCenterPluginthatenablesVMwareadministratorstoperformadvancedstoragemanagementandstorageoperationtasksdirectlyfromvCenter.

Figure2-3: vCenterPluginApplianceDashboard

NexentaStor5alsosupportsVMwareVirtualVolumes(VVOL)overNFSprotocolendpointsforscalability.NexentaStor5.1alsoaddssupportforVMwareSiteRecoveryManagerwithNexentaStor5HighPerformanceReplication.

2.4 OpenStackIntegrationNexentahasbeenanearlyandactivememberoftheOpenStackstoragecommunity,buildingitsfirstsetofCinderdriversfortheOpenStackEssexrelease,allthewaybackinApril2012.AstheOpenStackplatformhasmatured,sohasNexentaStorintegrationwithNexentaStor5supportingCinderoveriSCSIandNFSprotocols,aswellasManilastorageservices.

Figure2-4: OpenStackCinderoveriSCSIorNFS



2.5 StretchClustersandMetroHAConfigurationsForapplicationsthatrequirecontinuousoperations,NexentaStorMetroHAdeliverscontinuousavailability,synchronousmirroringandzeroRPOdisasterrecovery.ThesolutioncanbedeployedbetweensitesconnectedviaastretchedFibreChannelSANonthesamecampusorinthesamemetroarea,overdistancesupto50miles/80km.

Functionally,NexentaStorMetroHAstretchesaNexentaStorHAclusteracross2sites,withoneNexentaStorheadnodeineachsite.SASbackendstorageenclosuresinbothsitesareconnectedusinghighperformanceATTOTechnologyXstreamCOREFC75xxControllerstoasharedstretchedFibreChannelFabric.TheNexentaStorsoftwaremanagesthisFibreChannelbackendstorageandsynchronouslymirrorsdataacrossbothsitestoensurezerodatalossintheeventofadevice,nodeorsitefailure.

Thesolutionprovidesautomaticfailoverforclear-cutfailurescenariosandoperatordrivensitefailoverforsitewidedisastersituations.

Figure2-5:MetroHAwithFourATTOXstreamCoreControllers



3 UnifiedBlockandFileServices

3.1 StoragePoolingArchitectureNexentaStorSDSdeliverstrueunifiedblockandfilestorageservices.Physicalcapacityisorganizedinlogicalpoolsofstoragethatcansupportbothfilesystemsandblockvolumesconcurrently.AsingleNexentaStornodewithasinglebackendpoolcanthusconcurrentlydeliverblockandfileservicestoclientapplications.

NexentaStor5buildsonOpenZFSforitscoredatalayer.InatypicalNexentaStorHAcluster,thephysicalcapacitywillbeorganizedinoneortwostoragepools.Eachstoragepoolisacollectionofvirtualdevices(vdevs),whicharethemselvesmadeupofphysicaldevicesthatareconnectedtotheNexentaStornodes.NexentaStorbuildsonOpenZFStoprotectdataagainstsilentdatacorruption,providingstrongdataintegrity,automatedself-healing,andadvancedsoftware-baseddataprotection.

Selectingtherightpoolconfigurationboilsdowntobalancingthefollowing3items:

• Resiliencetodevicefailure(s):NexentaStorvdevscanbeconfiguredasmirrors,orwithsingleparity,dualparityortripleparityprotection.Apoolwithmirrorvdevscansustainasingledevicefailurepervdev.Itishoweverexposedtodatalossintheeventofadouble-failureinthesamevdev.Largerphysicaldevicestranslateintohigherrisksofhittingadoublefailureinagivenvdev.ThisisonereasonwhyNexentabestpracticesusedualparityconfigurationsorhigherforpoolsoflargeHDDs.

• Usablecapacity:apoolwithmirrorvdevswilluse50%ofrawcapacityinparityoverheadwhileapoolwith(4+2)dualparityvdevswillonlyspend30%ofrawcapacityonparityoverhead.Giventhesamerawcapacity,the(4+2)poolwillprovidemoreusablecapacity.

• Performance:ignoringtheeffectsofZIL,SLOG,ARCandL2ARC,alldatastoredinapoolisautomaticallystrippedacrossthesetofvdevsthatmakeupthepool.Morevdevsinapoolgenerallytranslateintohigherpoolperformance,particularlyforrandomIOworkloads.Putdifferently,giventhesamenumberofphysicaldevices,apoolwithmirrorvdevswillgenerallydelivermoreIOPSthanapoolbuiltwith(4+2)vdevs.

Figure3-1: NexentaStorStoragePools

TheexampleaboveshowsaNexentaStorHAclusterwith2hybridpools.PoolAisconfiguredwithmirrorvdevsandSSDbasedmirrorwritelog(slog)andreadcache(l2arc),whilepoolBisconfiguredwith(4+2)dual-parityvdevsandSSDbasedmirrorwritelog.



Filesystemsandblockvolumesarethencarvedoutofeachlogicalpool.Alldatastoredinapoolisautomaticallystripedacrossallvdevsinthepoolformaximumperformance.Thisallowsanydataset(filesystemorvolume),largeorsmall,togetaccesstothefullperformancecapabilityofthebackendpool.

NexentaStorappliancestypicallyrunwithafewlargepools(potentiallyscalinguptopetabytes)supportinglargefilesystems.Beingabletoscalepoolsandfilesystemsizesminimizesthenumberoflogicalentitiesthatneedtobemanagedandgenerallysimplifiesstoragemanagement.

Tosimplifysystemconfiguration,NexentaStor5supportsanewcreate-autofunctionthroughbothCLIandNexentaFusionthatautomaticallycreatespooldatavdevsbasedonuserprovidedcriteria.Forexample,usingthisfeatureausercanspecifyautomatedcreationofa“poolofRAID-Z2(4+2)vdevsacross1204TBHDDsacross3enclosuresencl_A,encl_Bandencl_Cwithenclosure-levelredundancy”.Thesystemtakescareoflayingoutallthevdevsintherightwayandautomatestheentiresetup.

3.2 PerformanceManagementNexentaisalongtimecontributortoOpenZFSacrossarangeofareascoveringdatamanagement,scalability,reliability,failuremanagementandperformance.NexentaStor5supportspoolsofSASSSDs,SASHDDs(generallyNL-SAS)andNVMeSSDs.Combiningmodernx86hardware,largeamountsofDRAMandfastSSDswithOpenZFSallowsNexentaStorhybridappliancestogenerallyout-performlegacystoragehardwareappliances.

OpenZFSwasspecificallydesignedtodeliveroptimalperformanceandavailabilityfromcommodityhardware.ItiswellknownforitshybridpoolperformancecapabilitiesanditsinnovativeuseofZFSIntentLog(ZIL),flashbasedsecondarylogdevices(SLOG),DRAMbasedreadcache(AdaptiveReplacementCache-ARC)andlargesizeflashbasedlevel2reachcache(L2ARC).

WhileextensiveinformationcanbefoundonlineontheinnerworkingsofOpenZFS,itisworthwhiletocalloutthefollowingwhenitcomestoperformanceandhybridpools:

• NexentaStormakesoptimaluseofallavailableDRAM.DRAMisprimarilyusedforreadcachingandtheAdaptiveReplacementCache(ARC).ARCconcurrentlyimplements2cachingalgorithmstooptimallyallocatememorytocachemostrecentlyusedandmostfrequentlyuseddata.Overthelastdecadeofusageinawiderangeofworkloads,ARChasprovenitseffectivenessanditsabilitytoout-performlegacyLeastRecentlyUsed(LRU)cachingimplementations.

• LessfrequentlyaccesseddataisstoredonSSDbasedL2ARCdevices.NexentaStorreferstotheL2ARCsimplyascache.Whencreatingastoragepool,youcandesignatedevicestobeusedasthecache.

• TheZFSintentlog(ZIL)accumulateswriteoperationsbeforefullwritetransactiongroupsareissuedtothebackendpooldevices.Tomaximizeperformanceofsmallsynchronouswriteoperations,hybridpoolsareconfiguredwithhighperformance,lowlatencySSDbasedsecondarylogdevices(SLOG)thatallowtheNexentaStornodetopro-activelyacknowledgewriteoperationstoclientapplications.

• InNexentaStor5,alldataiscompressedbeforebeingstoredonbackendmedia.ThedefaultalgorithmisLZ4,recommendedbecauseofitsperformanceandcompressionefficiencies.ARCoperatesoncompresseddata,furtheroptimizingitsuseofsystemDRAM.InNexentaStorHAclusters,SSDbasedlevel2ARCarealsopersistent,allowingcacheddatatobeimmediatelyavailabletoaNexentaStornodefollowingapoolfailover.



Oneimportantparameterwhentuningpoolsforperformanceinvolvesconfiguringthepoolanddatasetrecordsize.InNexentaStor5,thedefaultrecordsizeforfilesystemsis128KB.Forvolumes,itis32KBbasedonthefactthatFCandiSCSILUNsaremoregenerallyusedforapplicationsandworkloadsthatgeneratesmall(er),randomIOs.Forstreamingtypeworkloadssuchaslargebackupandarchiveorlargevideostreamingsystems,NexentaStor5supportslargerrecordsizes,allthewayto1MB.

NexentaStor5supportsbothinlinecompressionandinlinededuplication.Inlinecompressionisenabledbydefaultonallstoragepoolswiththehigh-performanceLZ4algorithmbydefault.Inlinededuplicationcanbeusedbutisgenerallyrecommendedforlowercapacityappliances.NexentaStor5continuallymonitorsthesizeofthededuplicationtableandautomaticallyturnsoffdeduplicationifitdetectsariskofthededuplicationtablespillingoutoffastDRAMontoslowerpoolstorage,therebyprotectingthesystemfromunexpectedperformancedegradations.

Tofurtherfacilitatestoragepoolconfiguration,NexentaStor5includesprofilescontainingsettingstunedespeciallyforagivenstoragetype:All-FlashandGeneric.Forexample,ifyourNexentaStorappliancehasallSSDstoragedevices,youcanapplytheAll-Flashprofile,whichoptimizesperformanceforthiskindofconfiguration.AllstoragepoolsyousubsequentlycreateontheNexentaStorappliancewillautomaticallyhavetheprofilesettingsappliedtothem.

Forall-SSDconfigurations,NexentaStor5supportsautomatedorscheduledTRIM/UNMAPonthebackendSSDs.ForsomeSSDs,thiscanhelpmaintainperformance,lowerI/Olatency,andincreasetheusefullifeoftheSSDsinthepool.ThisfeaturecanalsobeusedforpoolsconfiguredontopofthinLUNspresentedbyabackendstoragearraythatsupportsUNMAPoperationstoreclaimunusedcapacityinthebackendarray.

3.3 DeviceFailureHandlingAsmentionedabove,besidesperformance,theothermainobjectiveofstoragepoolconfigurationisdurabilityandprotectingdataanddataservicesfromdevicefailures.NexentaStorsupportsraid0striped,mirror,single-parity,dual-parityandeventripleparitypoolconfigurations.

Asoflate2017,NexentaStor5referencearchitecturessupportNL-SASHDDsrangingfrom2TBallthewayto12TB.Poolsof2TBHDDsaregenerallyconfiguredwithmirrorvdevs,whilepoolswithdiskslargerthan4TBgenerallygetconfiguredwithdual-parity(4+2),(6+2)orlargervdevs.Animportantconsiderationinthevdevconfigurationiswhetherthesystemshouldberesilienttolossofafullstorageenclosure.Forexample,aphysicalsetupwith3separatestorageenclosurescansupporta(4+2)poolwithenclosurelevelredundancy(nomorethan2disksperenclosureforagivenvdev).

NexentaStorsupportstheallocationofanynumberofhotsparedevicestoapool.BothSSDsandHDDscanbeconfiguredashotsparesinahybridpool.Intheeventofadevicefailureinapool,NexentaStor5willautomaticallyactivatethe‘best’hotspare:aspareofthesametype(SSDorHDD),ofthesamesizeandpreferentiallyinthesamestorageenclosureasthefaileddevice.

NexentaledtheworkinOpenZFSonresilverperformance,enablingdeviceresilver(akadevicerebuilds)operationstogoasfastasthedevicecanhandlesequentialIOs.ThisNexentaStor5enhancementisparticularlycriticalforpoolswithlargeHDDstoreducedataexposuretofaileddevices.



3.4 DataatRestEncryptionNexentaStor5supportsdataatrestencryptionforpoolsbuiltwithTCGEnterpriseSelf-EncryptingDrives.Thesolutionistransparenttoallotherfeaturesanddoesnothaveanyimpactonoverallsystemperformance.Fordataatrestencryptiontobeenabledonaparticularpool,alldevicesinitmustbeSEDcompliant,includingtheSSDsusedasSLOGorL2ARCdevicesinhybridpools.

Figure3-2:DataatRestEncryptionOverview

ThesolutionreliesonanexternalKMIPcompliantkeymanagementinfrastructure(e.g.KeySecurefromGemalto)toprovidethekeysrequiredtoaccessdataonthepooldevices.

3.5 FileSystemsandSharedFileServicesANexentaStorfilesystemisadatasetconfiguredinastoragepooltoprovidePOSIXcompliantstorageoffilesanddirectories.NexentaStorbenefitsfromOpenZFS’advanceddataintegrity,functionality,andscalability.Asaresult,NexentaStorsupportsfilesystemsofvirtuallyunlimitedsizes(effectivelyonlylimitedbythephysicalsizeofapool),easilyscalingtohundredsofterabytesandevenpetabytes.

Bydefault,filesystemsshareallthecapacityintheunderlyingpoolformaximumflexibility.ClientsaccessthefilesanddirectoriesusingstandardSMBandNFSprotocols.MicrosoftWindowsclientscommonlyuseSMBtoaccessfilesystemdata,whileclientsusingUNIXandUNIX-likeoperatingsystemscommonlyuseNFS.

ANexentaStorfilesystemhasanumberofpropertiesassociatedwithit.Thesepropertiescontrolsuchthingsasinlinecompressionsettings,defaultblocksizeforfilesinthefilesystem,users,groups,accesscontrollists,quotas,reservations,ICAPvirusscanning,andsoon.UsingtheNexentaStorAPIandCLI,youcansetthesepropertieswhenyoucreatethefilesystem,oryoucanmodifythemasneeded.



Youcanconfiguremultiplefilesystemswithinastoragepool,andafilesystemcanhaveadditionalfilesystemsnestedbelowit(upto16levelsdeep).Bydefault,nestedfilesystemsinheritthepropertiesoftheirparent.Nestedfilesystemscanalsobecombinedwithdataprotectionservicessuchassnapshotandreplicationschedulestomaintainwriteconsistencyacrossthefullhierarchywheneversnapshotsaretakenontheparentfilesystem.

3.5.1 SharedFileServicesToallowWindowsclientsaccesstodatainaNexentaStorstoragepoolusingtheSMBprotocol,youcancreateafilesystemandconfigureSMB-relatedsettingsforthefilesystem,suchasaworkgrouptojoin,ActiveDirectorydomain,sharenames,etc.NexentaStor5providesSMBservicesthroughaNexentadevelopedkernelbasedSMBserverforbetterperformanceandscalability.

NexentaStor5shipswithSMB2.1asthedefaultSMBprotocolversionandaddssupportforSMB3toprovideahigh-performance,file-basedstoragebackendforMicrosoftHyper-Venvironments,includingOffloadedDataTransfer(ODX)toaccelerateHyper-VcopyoperationsoverSMB3.

ToallowclientsrunningUNIXandUNIX-likeoperatingsystemstoaccessstoragepooldatausingtheNFSprotocol,youcanconfigureNFSpropertiesforafilesystem.NexentaStor5supportsNFSv3(default)andNFSv4throughamature,highperformancekernelbasedNFSserver.

3.5.2 AccessControlListsNexentaStorimplementsNFSv4-styleACLsonitsfilesystems.Afilesystem’sACLconsistsofoneormoreAccessControlEntries(ACEs)thatspecifywhichusersandgroupsareallowedtoread,write,andmodifyfilesanddirectoriesinthefilesystem.YoucancreateandmodifyindividualACEsusingtheNexentaStorCLIandAPI.

NexentaStorACLsarecompatiblewithbothNFSandSMB,sothattheACLyoucreateforafilesystemappliestoclientsusingeitherprotocol.Thisprovidesthefoundationforfull-featured,concurrentSMBandNFSsharingofNexentaStorfilesystemsusingMicrosoftIDMapping.

3.5.3 Quotas,ReservationsandCapacityManagementAcriticalimplicationoftheNexentaStorpoolingmodelisthatallfilesystemspotentiallyhaveaccesstoallavailablecapacityinthepool.Thisisapowerfulfeaturethatcangreatlysimplifycapacitymanagementinalargesystem:ratherthanmanagingcapacityateachindividualfilesystemlevel,thestorageadministratorcansimplymonitoravailablecapacityattheaggregatepoollevel.

AnimportantOpenZFSbestpracticeistokeeputilizationofstoragepoolsbelow80%.Asacopyonwrite/redirectonwritefilesystem,OpenZFSneedsacertainamountofheadroomtoeffectivelymanageavailablespaceinastoragepool.Pushingutilizationabove85%willgenerallytranslateindegradedperformanceandhigherlatencies,particularlyonall-diskandhybridpools.

Tocontrolhowmuchcapacityaparticularfilesystem,aparticularuseroraparticulargroupcanconsume,NexentaStorsupportsconfiguringquotasandreservations.Areservationpro-activelycarvesoutcapacityfromthepoolandkeepsitasideforthesaidfilesystem.Aquotaontheotherhanddefinesthemaximumamountofcapacitythataparticularuserorgroupisallowedtoconsume.



3.5.4 StorageQoSForFileServicesNexentaStorall-flashconfigurationsservingouthighperformance,lowlatency,NFSdatastorestoVMwarevSphereprivatecloudsisaverypopularusecase.ItispopularbecauseusersgetthemanagementsimplicityofNFSVMwaredatastores,withtheperformanceandeaseofuseofall-flash,andthecostsavingsofrunningsoftware-definedstorageonindustrystandardserversandSSDs.Forhostingprovidersrunninglarge-scalemulti-tenantvirtualizedinfrastructure,all-flashstoragealsohasthebenefitofsimplifyingday-to-dayoperationsandpracticallyeliminatingstoragerelatedcustomerescalations.

Insomeinstanceshowever,thereisaneedtocontrolstorageperformanceforsometenants;eithertoensurefairsharingofthebackendstorageresourcesbetweentenants,orensurethattenantsgetaccesstotheresourcestheyareentitledto,andnotmuchmore.Fortheseenvironments,NexentaStor5supportsQualityofServiceforfileservices.

Figure3-2:ExampleUseCaseforNexentaStorStorageQoS

Intheexampleabove,NexentaStorQoSisusedtodeliverdifferentiatedstorageperformancebetweenacoupleoftenants.TenantAhasaccesstoNFSdatastoreDS1whileTenantBhasaccesstoNFSdatastoreDS2.OnNexentaStor,DS1isconfiguredtoprovideupto300MB/sofbandwidthwhileDS2isconfiguredtoprovidenomorethan100MB/sofbandwidth.

ConfiguringQoSontheNexentaStorNFSshareallowsthehostingprovidertoeffectivelycaptheaggregatestorageresourcesconsumedbyaparticulartenantwhileleavingconfigurationofVirtualMachinelevelQoS(betterenforcedbythehypervisor)uptothetenantitself.



3.6 VolumesandSharedBlockServicesSimilartohowfilesystemsaresupportedonstoragepools,NexentaStorsupportsthecreationofrawblockvolumesonstoragepools,tobesharedaseitheriSCSIorFibreChannelLUNs.Aswithfilesystems,youcanusetheNexentaStorCLItoconfigurepropertiesforvolumessuchasblocksize,compressionmode,andwhetherthevolumeisread-only.AllvolumesconfiguredonaNexentaStorpoolarethinbydefault.Configuringareservationonavolumewilleffectivelymakeitthick.

3.6.1 VolumeGroupsNexentaStor5requiresthatallvolumesbecontainedwithinapredefinedvolumegroup.Volumegroupssimplifytheprocessofconfiguringvolumesbyallowingyoutosetpropertiesonceatthevolumegrouplevelandrelyonpropertyinheritancefortheunderlyingvolumesinthegroup.

Forexample,tochangethecompressionpropertyforthevolumesinavolumegroup,youcouldsimplychangethevolumegroupcompressionpropertyratherthaneachvolume’scompressionproperty.Whenyousetthepropertyforthevolumegroup,allunderlyingvolumesinthegroupautomaticallyinheritit.

Volumegroupsalsoprovidethecriticalfunctionofconsistencygroupsfordataprotectionservices,providinganaturalcontrolpointfortransactionlevelconsistentsnapshotsacrossallunderlyingvolumes.Forexample,NexentaStorcanbeconfiguredtotakerecursivesnapshotsofallvolumesinavolumegroupaccordingtoaschedule.Thesnapshotscanbeclonedorrolledbackfortheentirevolumegroupatonce.

3.6.2 iSCSIBlockServicesNexentaStorvolumescanbesharedasiSCSILUNs.Todothis,youfirstcreateoneormoreiSCSItargetswithinNexentaStor,specifyingtheirassociatednetworkportal(s).NexentarecommendscreatingoneiSCSItargetperIPinterfaceintendedtosupportiSCSItraffic.

YouthenaddtheiSCSItargetsyoucreatedtoaniSCSItargetgroup.AniSCSItargetgroupisagroupofoneormoreiSCSItargetsthatwillprovideaccesstoasetofvolumes.NexentaStoralsoallowsyoutoconfigureiSCSIhostgroups,whicharegroupsofoneormoreiSCSIinitiators.



Finally,youspecifyoneormoremappingsbetweenthevolumeandtheiSCSItargetgroupandiSCSIhostgroupsandLUNidentifier.TheinitiatorsintheiSCSIhostgroupthenhaveaccesstothevolumeusingtheLUNidentifieronthespecifiediSCSItargetgroup.TherelationshipbetweeniSCSItargets,iSCSItargetgroup,hostinitiatorgroupsandmappingsisshownbelow:

Figure3-3:TypicalNexentaStoriSCSIConfiguration

InaNexentaStorHAcluster,iSCSItargetsshouldbecreatedonVirtualIPaddressessothattheiSCSItargetsandiSCSItargetgroupsthatcontainthemcanseamlesslyfailoverbetweennodes,withthebackendstoragepoolcontainingthevolumestheyaresharing.

3.6.3 FibreChannelBlockServicesNexentaStor5supportsimplicitALUAconfigurationswhensharingFCLUNs.InordertosharevolumesasFCLUNs,yourlicensemustincludetheoptionalFibreChannelTargetfeature.ThisallowsyoutocreateFibreChanneltargetgroupsthatcontainFCtargetsfrombothnodesofaNexentaStorHAcluster.

SimilartohowlogicalmappingsaremanagedwithiSCSI,creatingFibreChannelhostgroupsandFCLUNmappingsthatcombineaFCtargetgroupwithaspecificFChostgroupandvolumeprovidegranularcontrolofLUNvisibilityacrosstheFibreChannelfabric.



4 NexentaStorDataProtection

4.1 InstantSpaceOptimizedSnapshotsandClonesNexentaStorsupportsvirtuallyunlimitednumbersofhigh-performance,space-efficient,instantsnapshotsandclones.Itispossibletotakeindividualsnapshotsoffilesystemsandvolumestogetcrash-consistent,point-in-timecopiesoftheircontent.

Recursivesnapshotscanalsobetakenonnestedfilesystemsorvolumegroupstogettransaction-consistent,point-in-timecopiesofalltheirunderlyingchildrenfilesystemsorvolumes,respectively.

Figure4-1: NexentaStorHierarchicalDataConsistency

Asnapshotisaread-onlyrepresentationofadataset(thatis,afilesystem,volumegroup,orvolume)ataspecificpointintime.Snapshotsdonotconsistoftheactualdata,butpointerstowherethedataislocatedintheunderlyingpool.Becausetheydonotcontaindata,snapshotsaremuchsmallerinsizethanthedatatheyreference,allowingNexentaStortocollectandmaintainapracticallyunlimitednumberofsnapshots.

Snapshotscanbecloned.Whenyoucloneasnapshot,itcreatesanewdatasetthatisinitiallypopulatedwiththecontentsofthesnapshot.Unlikesnapshots,clonesarewritable,sothatyoucanadddatatothemasnecessary.

Acloneislinkedtotheoriginalsnapshotsothattheoriginalsnapshotcannotbedeletedwhileanyclonesofitexist.Aclonecanbepromoted,whichmakesitindependentofitsoriginalsnapshot.

UsingtheNexentaStorsnapshotrollbackfeature,youcanrestoreadatasettothestateitexistedinanyofthesnapshotsretainedontheappliance,assuringthatallversionsofthedatacapturedbysnapshotsareprotected.



4.2 SnapshotServicesSnapshotsofadatasetcanbecreatedasneededusingtheCLIorRESTAPItools.NexentaStor5alsosupportsadvancedscheduledsnapshotservices(alsocalledsnappingjobs),whichcollectsnapshotsonarecurringbasisandspecifyhowmanysnapshotstomaintainperschedule.Scheduledsnapshotservicesareconfiguredtotakesnapshotsaccordingtoapredefinedschedule,fromeveryminutetoeveryhour,day,weekorevenmonth.

Snapshotservicesprovidegreatscaleandflexibility.Agivendatasetcanbeconfiguredwithmultiplesnapshotschedules,eachwithitsownretentionpolicyspecifiedintermsofnumberofsnapshotstokeep.Forexample,arecursiveservicecouldbeconfiguredonavolumegroupwith3schedules:“every2hours,keep12”,“everyday,keep7”and“everySaturday,keep52”.Thiswouldresultinayear’sworthofdataretention,with52weeklysnapshots,dailysnapshotsforthepastweekandbi-hourlysnapshotsforthepast24hours.

4.3 HighPerformanceReplicationOverviewNexentaStor5HighPerformanceReplication(HPR)providesfullfeatured,highperformanceremotereplicationfordisasterrecoveryoveranydistance.TheNexentaStor5replicationenginehasbeenmovedtotheoperatingsystemkernelformaximumperformanceandfine-grainedcontrolofRecoveryPointObjectives.Theresultisasolutionthatsupportedtwotypesofreplicationservices:

• ScheduledReplication(SR)–thisissnapshotbasedscheduledreplicationthat,withtherightlicenseoption,canbeusedforRecoveryPointObjectives(RPO)aslowas1minute.

• ContinuousReplication(CR)–thisiscontinuousasynchronousreplicationthat,withtherightlicenseoption,candeliverclosetozeroRPOoveranydistancewithoutaffectingapplicationperformanceontheprimarysite.CRworksbyasynchronouslyreplicatingeverywritetransactiongrouponthesourcedataset.

Asshownintheexamplebelow,HPRservicescanbeconfiguredbetweenfilesystems,volumesorvolumegroupsandaremanagedatthedatasetlevel,allowingbi-directionalreplicationbetweensites,albeitbetweendifferentsourceanddestinationdatasets.

Figure4-2:High-PerformanceReplicationExample



HPRservicescaneitherbeconfiguredonaparticularfilesystemorvolume,ortheycanbesettorunrecursivelyonaparentfilesystemandallitsnestedchildrenfilesystems,oronavolumegroupandallthevolumesitcontains.Thisguaranteeswritetransactionlevelconsistencyacrossthesetofnesteddatasetsandcanbeusedtoimplementapplicationlevelconsistencygroups.

Figure4-3:ApplicationLevelConsistencyGroupsandHPR

NexentaStorHighPerformanceReplicationservicescanbeconfigured:

• Tomovedatasetsbetween2poolsonthesameNexentaStorappliance• ToreplicatedatasetsbetweenNexentaStorHAclusters• ToreplicatedatasetsbetweenamixofNexentaStorHAclustersandsinglenodeappliance

4.4 LicensingConsiderationsforHPRHighPerformanceReplicationissupportedbetweensystemsrunningNexentaStorversion5andabovewithEnterpriseEditionlicenses.

AsystemwiththebaseEnterpriseEditionlicensewillsupportScheduledReplicationservicesdeliveringRPOaslowas15minutes.

AsystemwiththeEnterpriseEditionlicenseandtheadditionalcontinuousreplicationoptionprovidessupportforScheduledReplicationwithRPOaslow1minute,aswellasContinuousReplicationservicesfornearzeroRPOoveranydistance.



4.5 ScheduledReplicationServicesNexentaFusionandtheNexentaStorVMwarevCenterpluginprovidesimpleconfigurationandmanagementofHPRservices.MoreadvancedconfigurationoptionsareavailableusingtheNexentaStorCLIandRESTAPI.

BeforeconfiguringHPRservices,youmustensurethatallNexentaStorappliancessharethesameReplicationpassword.Thissharedpasswordistypicallysetatsoftwareinstallationtime.ItcanalsoberesetatanytimeusingtheNexentaStorCLI.ThesharedReplicationpasswordprovidesasimplecontrolmechanismtoprotectNexentaStorappliancesfromunauthorizeddatatransfers.

Ascheduledreplication(SR)serviceisdefinedbythePrimary(typicallysource)andSecondary(typicallydestination)datasetsandasetofoneormoreschedules.WhenascheduleiscreatedaspartofaSRservice,theuserspecifieshowmanysnapshotsforthatschedulemustbekeptonthePrimaryandontheSecondarysite.Itisimportanttonotethattheretentionpolicyissite-specificanddoesnotchangedependingonthedirectionofthereplicationstreams.

Figure4-4:ScheduledReplicationServicewithSiteSpecificRetentionPolicies

ByallowingmultipleschedulestobeconfiguredaspartofaSRservice,itispossible,forexample,toconfigureaservicewithanhourlyschedulethatkeeps12snapshotsonPrimaryand24onSecondary,andadailyschedulethatkeeps7snapshotsonPrimaryand30onSecondary.

NexentaStorSRservicesonlyreplicatethesnapshotsthatarecreatedaspartoftheservice.Snapshotscreatedonthesourcedataset(bylocalsnappingjobsforexample)arenotreplicatedbyHPR.

AspartofaSRservice,itispossibletocreateanon-demandsnapshotandhaveitimmediatelyreplicatedtothedestinationdataset.Schedule-specificretentionpoliciesdonotapplytotheseon-demandsnapshots,andtheymustbemanaged(i.e.eventuallyremoved)bytheenduser.



WhileaSRserviceisactive,theusermaycreateacloneoutofanyofthesnapshotsonthedestinationdataset.Suchclonescanbeusedfordisasterrecoverytesting,forexample:

Figure4-5:ScheduledReplicationServicewithnon-disruptiveDRTest

Whileacloneexists,itsparentsnapshotisprotectedandwillbekeptonthedestinationdataset,independentoftheconfiguredretentionpolicy.Oncethecloneisdeleted,itsparentsnapshotisautomaticallyreturnedtotheSRserviceandwillbekeptordeletedaccordingtotheretentionpolicyoftheschedulethatoriginallycreatedthesnapshot.

ItisalsopossibletosharethedestinationfilesystemofanactiveHPRserviceas‘read-only’,allowingnon-disruptiveaccesstoitsdataforbackupandrestoreusecases.

HPRisarobustsolutionthatcanrecoverfromwidevarietyofunexpecteddisruptions,includingfullsiteoutages,aslongastherearecommonsnapshotsbetweenthePrimaryandSecondarysites.TheNexentaStorhprrecoverCLIcommandprovidesasimplesolutiontoautomaticallyrestartareplicationservicethatisinterruptedbychangesmadetothesourceordestinationdatasets.

AnotherimportantreliabilityfeatureofHPRistheabilitytoautomaticallyresumefrominterruptionsoflongrunningsnapshottransfers(forexample,duringtheinitialsynchronizationoperation):HPRisabletoautomaticallyrestartfromwhereitleftoffoncenetworkconnectivityisrestoredwithouthavingtoretransmitpreviouslytransferreddata.

4.6 ContinuousReplicationServicesContinuousReplicationservicescanbeconfiguredonfilesystems,volumesandvolumegroups.Therearenoschedules,retentionpolicies,orvisiblesnapshotstomanagewithCRservices,makingthemseeminglymuchsimplertooperatethanScheduledReplicationservices.

ItispossibletoconcurrentlyconfigurebothaCRandaSRserviceonthesamesourcedataset,replicatingto2differentdestinationdatasets,possiblyonthesameNexentaStorsystem.Insuchaconfiguration,theCRserviceprovidesnearzeroRPOprotectionfordisasterrecoverywhiletheSRservicecanbeusedformoretraditionalbackupandrestoreusecases.



4.7 Multi-DestinationNexentaStorHPRsupportsmulti-destinationconfigurationsbyallowingmultipleSRservicestobeconfiguredonthesameprimarydataset.HPRdoesnotsupportcascadedreplication,however,sothestateofthevariousSRservicesthatshareacommonprimarydatasetmustbeconsistentwiththatlimitation.

Oneandonlyonecontinuousreplication(CR)serviceisallowedonaprimarydataset.However,HPRsupportshavingoneCRandoneormoreSRservicesconfiguredonthatprimarydataset,enablingconfigurationswhere,forexample,datasetAiscontinuouslyreplicatedtositeB,andreplicatedeverydaytositeCviaaseparateSRservice.

Figure4-6:HPRMulti-DestinationConfigurations

4.8 MovingDatasetToandFrom3rdPartyOpenZFSSystemsIndependentofHPR,NexentaStor5alsosupportstransfersofsnapshotsusingstandardOpenZFSsend&receiveoversshtoandfromsystemrunningstandardOpenZFSonLinux,FreeBSDorillumos.

Figure4-7:SnapshotTransferUsingStandardOpenZFSsend&receive

ContrarytoHPR,thisfeaturecanonlybeusedforon-demandsnapshottransferanddoesnotsupportschedules,orautomaticretentionpolicies.



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