Въведение
Software-definedstorage(SDS)isadatastoragemethod.Allstorage-relatedcontrolworkisonlyintheexternalsoftwarerelativetothephysicalstoragehardware.Thissoftwareisnotusedasfirmwareinastoragedevice,butonaserveroraspartofanoperatingsystem(OS)orhypervisor.
Software-definedstorageisamajorindustrydevelopmenttrend.Thisindustryalsoincludessoftware-definednetworking(SDN)andsoftware-defineddatacenters(SDDC).SimilartotheSDNsituation,software-definedstoragecanensurethatsystemstorageaccesscanbemanagedmoreflexiblyatanaccuratelevel.Software-definedstorageisabstractedfromhardwarestorage,whichalsomeansthatitcanbecomeasharedpoolthatisnotrestrictedbythephysicalsysteminordertomakethemostefficientuseofresources.Itcanalsobedeployedandprovisionedthroughsoftwareandmanagement,oritcanbefurthersimplifiedthroughpolicy-basedautomatedmanagement.
Трудност
Използването на софтуерно дефинирано хранилище за дългосрочно съхранение е пълно с рискове, като грешки на битови данни, откази на твърд диск, мрежови атаки, човешка грешка и природни бедствия. Въпреки това, в допълнение към горните рискове, дългосрочното съхранение на данни трябва да вземе предвид и други проблеми, като промени в хардуерната архитектура, софтуерни платформи, приложения и формати на данни.
Atthesametime,theincreasingdemandfordataaccessibility,synergy,andbigdataanalysismakestheproblemnotonlyatthestoragetimelimitlevel,butalsoconsideringitsavailability.
Manyenterprisedatacentersareundergoingatransformationfromtraditionalarchitecturetocloudarchitecture.Intheprocessoftransformation,storageisoftenthemostimportantanddifficultpart.Usersneedtousesoftwaredefinitionstounlockvendorlocks,eliminateproprietaryplatforms,andreduceincreasingcomplexity,soastoconvertphysicalstoragedevicesintostorageresourcesforcloudcomputing.Atthesametime,howtorealizetheunifiedmanagementofstorageandthefreeflowofdatabetweentheenterprise'sself-builtdatacenter,outsourcingdatacenteranddifferentcloudserviceprovidersisalsoamajorchallengeintheimplementationofcloudcomputing.
Предимства
Software-definedstorageallowscustomerstointegratestorageservicesintothesoftwarelayeroftheserver.Software-definedstorageextractssoftwarefromtheoriginalstoragecontroller,allowingtheirfunctionstobefurtherdevelopedandnotlimitedtoasingledevice.Comparedwithsoftware-definedstoragethatlimitsdatadeduplicationorthinprovisioningtoasingleharddrive,comparedtoextendingittotheentirestorageplatformlevel,theformerisreallymeaningless.Atthispoint,thepractitionersofsoftware-definedstoragehavenotdraggedeveryonedown.
Oneofthegreatbenefitsofsoftware-definedstorageistostripthesoftwarefunctionfromthearraycontrollersothatitcanbeusedtomanageallthestorageinthedatacenter.
Buttherearestillmanywaystoobtainsoftware-definedstorage.Amongthem,thesoftware-definedstoragedevicemodelthathasreceivedwidespreadattentionrecentlyhasbeenfrequentlyexposed.Anotheradvantageofsoftware-definedstoragedevicesisthatmigrationiseasier.Unlikeothersoftware-definedstorageconfigurations,software-definedstoragedevicesdonotrequiredatatobecopiedtoeachnode,thatis,itdoesnotrequireadditionalstoragespace.Dataisonlystoredinonelocation,andthereisnoneedtocopytheapplicationfromonelocationtoanother.
Butsoftware-defineddevicesareusuallyproprietary,whichiswhatmanyITexpertshopetoavoidintheadoptionofstoragetechnology.
Скрити разходи
However,theindustryrarelymentionsthepotentialhiddencostsrelatedtoSDS.ThehardwaremixingandmatchingthatSDSmaybringwillreversethecostorriskofintegratingsoftwareandhardwaretoendusers.WhenchoosingSDSproducts,itiscriticaltoevaluatewhetherthemanufacturercanprovidethebenefitsofSDS.Timesandtechnologyhavechangedtosomeextent,andsomepeoplesaythatthedrivestandardhasbeenimproved.ButIthinkthatnewhardwaretechnologies,suchassolid-statestorage,areevolvingeveryday.Ifweextendtheabstractionabilityofstoragesoftwaretothemaximum,itshouldbeabletocoordinateanyhardware.IfthisistheidealstateofSDSdeployment,thenthepossibletechnologycombinationsinasystemwillbeunlimited.Underthisassumption,theresponsibilityandcostofverifyingandintegratingnewhardwaretechnologieswillallbeattributedtoIT.
Три избора
Thefirstchoiceforsoftware-definedstorageistointegratewiththehypervisororexistaspartofitsstack.VMwarehascurrentlydevelopedVirtualSAN,andthecompany'sso-calledsoftware-definedstoragelayerexistsaspartofitssoftwarestack.Hyper-Vhasso-calledclusterstoragespaceandisdirectlyintegratedintoMicrosoft'sHyper-Vstack.
Thesecondsoftware-definedstoragearchitectureincludesthird-party,hypervisor-independentproducts.TheycanworkwithVMware,Hyper-V,KVM,orCitrixproducts.Somesoftwareproductshavecompletefunctions.Itevensurpassesleadingmanufacturersinsomerespects,suchasMaxta,StarwindSoftware,andStoreMagic.Theyprovidethesamefunctionality,butarenotdedicatedtoaparticularhypervisor.Thestoragewarehousestheycreatecanbesharedamongmultipledifferenthypervisors.
Thethirdtypeisvirtualstorage,whichhasbeenaroundforalongtime.ThistypeincludesIBMSpectrumVirtualizeandDataCoreSANsymphonyproducts,whichvirtualizeallhardwareresourcesandabstractthemintoasoftwarelayertoallocateresourcesmoreefficiently.Whenanapplicationloadneedstoconfigurestoragewithaspecificdataprotectionmechanism,youonlyneedtoselecttheconfigurationfromthemanagementinterface,anditwillbeautomaticallyallocatedwiththestorage.
Концепцията за софтуерно дефинирано хранилище е огромна. В момента много форми на продукти за съхранение в полето за съхранение, като виртуализация на хранилище, ServerSAN и хиперконвергирана архитектура (HCI) са част от SDS.
1. Контролна равнина (контролна равнина)
На нивото на SDSControlPlane по-известните са:
1)VMwareSPBM(StoragePolicyBase)Management,managementbasedonstoragestrategy);2)OpenStackCinder,CinderisacomponentoftheOpenStackcloudplatformtoprovideblockstorageservices;CindercanaccessmostSANstorageproductsintheindustrythroughaunifiedstoragesoftwareinterface.3)AtypeofstoragemanagementsoftwarerepresentedbyEMCViPR.Thegoalistorealizetheunifiedmanagementofstorageproductsofasinglestoragebrandormultiplestoragebrands,andthepoolingandintegrationofstorageresourcessuchasheterogeneousstoragespace.
2.DataPlane
AttheSDSDataPlanelayer,therearemultiplestorageformsinvolved.
1) Въз основа на стоков хардуер (на базата на търговски хардуер), тази част съдържа две основни категории:
HyperConvergedArchitecture(HCI),трябва да бъдеServerSANПо-известните подмножества са:VMwareVSANилиEVO:RAIL,EMCScaleIO,Nutanix,Maxta и др.
Нехиперконвергентна архитектура, която е независима разпределена система за съхранение, по-известните са DELLFluidCache, HPStorVirtual, RedHatInktankCeph, InspurAS13000 и др.
Традиционен SAN/NAS (външно хранилище), включително SAN хранилище или NAS хранилище
Throughacquisitionorself-development,theSDSabstraction(decoupling),pooling,andautomationphasesaregraduallyrealizedTypicalexamplesincludeHPdecouplingLeftHandfromtheoriginalhardwaretoformtheVSAversionofStorVirtual;NetApplaunchedtheVSAversionofONTAPEdgeVSAofDataONTAP;IBMlaunchedtheXIVsoftwareversionofSpectrumAccelerate;DataCoreSANsymphony;EMClaunchedthevirtualizedversionofVNXvVNXWait.
Cloud/ObjectStorage
UseRESTfulAPIandotherinterfacestoinputandoutputdatawithobjectstorage.TherearecurrentlythreeRESTfulAPIs:AmazonS3,SNIACDMIandOpenStackSWIFT.Themorefamousonesare:EMCAtmos,InspurAS13000andsoon.
Принципи на изграждане
Software-definedstorage(SDS)technologymayprovideameanstomakestoragemoreflexibleandagile,sovirtualstoragevolumescanbecreatedontheflyandworkwitheaseLoadsareassociatedandmovedorconvertedtogetherwithvirtualmachinesbetweenservers.Inaddition,SDSenablesyoutoassociatevalue-addedserviceswithvirtualstoragevolumes(tonameafew,theseservicesmayincludemirroring,replication,thinprovisioning,anddeduplication/compression),sothatstorageapplicationsareastailor-madeTheneedsoftheworkload.Inaddition,agoodSDStechnologyshouldprovidepathmanagementandinterconnectionloadbalancingtomakebetteruseofphysicalstoragedevicesandserversthateitherhostphysicalworkloadsorvirtualizedclients(orboth)Networkandstructuralconnectionsbetween.
Цел
Thegoalofsoftware-definedstorage(SDS)istoseparatestorageapplicationsfromthephysicaldatastorageinfrastructure.Intheory,thiswillachieve"flexible"allocation,reallocation,andnon-allocationofstorageresources.Inotherwords,SDSprovidesawaytoseparatestorageservicesfromstoragepackages.Evenifthebasichardwareandinterconnectionarechanged,itcanstillprovidevolumecontinuity.
Thiscapabilityisespeciallysuitableforapplicationsthatareextractedfromserverhardwareor"virtualized"andcanbemovedbetweenservers,networks,orstoragestacks.
ByusingSDS,forphysicalresources,thestoragevolumepresentedtoavirtualizedworkloadoraclientisitselfanabstractionlayer,ratherthanaphysicalconnection.ThisSDSvolumecanbemovedbetweenhoststogetherwiththeworkload,providinganewpathwiththesameonlinestorageresourcesthroughtheSDSservice.Therefore,itisnotnecessarytocopythedataofeverypossiblehost.