Úvod
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.
Obtížnost
Použití softwarově definovaného úložiště pro dlouhodobé ukládání je plné rizik, jako jsou datové bitové chyby, selhání pevných disků, síťové útoky, lidské chyby a přírodní katastrofy. Kromě výše uvedených rizik však dlouhodobé ukládání dat musí vzít v úvahu i další problémy, softwarové a softwarové aplikace, například změny datových forem, hardwarové architektury, formáty dat.
Atthesametime,theincreasingdemandfordataaccessibility,synergy,andbigdataanalysismakestheproblemnotonlyatthestoragetimelimitlevel,butalsoconsideringitsavailability.
Manyenterprisedatacentersareundergoingatransformationfromtraditionalarchitecturetocloudarchitecture.Intheprocessoftransformation,storageisoftenthemostimportantanddifficultpart.Usersneedtousesoftwaredefinitionstounlockvendorlocks,eliminateproprietaryplatforms,andreduceincreasingcomplexity,soastoconvertphysicalstoragedevicesintostorageresourcesforcloudcomputing.Atthesametime,howtorealizetheunifiedmanagementofstorageandthefreeflowofdatabetweentheenterprise'sself-builtdatacenter,outsourcingdatacenteranddifferentcloudserviceprovidersisalsoamajorchallengeintheimplementationofcloudcomputing.
Výhody
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.
Skryté náklady
However,theindustryrarelymentionsthepotentialhiddencostsrelatedtoSDS.ThehardwaremixingandmatchingthatSDSmaybringwillreversethecostorriskofintegratingsoftwareandhardwaretoendusers.WhenchoosingSDSproducts,itiscriticaltoevaluatewhetherthemanufacturercanprovidethebenefitsofSDS.Timesandtechnologyhavechangedtosomeextent,andsomepeoplesaythatthedrivestandardhasbeenimproved.ButIthinkthatnewhardwaretechnologies,suchassolid-statestorage,areevolvingeveryday.Ifweextendtheabstractionabilityofstoragesoftwaretothemaximum,itshouldbeabletocoordinateanyhardware.IfthisistheidealstateofSDSdeployment,thenthepossibletechnologycombinationsinasystemwillbeunlimited.Underthisassumption,theresponsibilityandcostofverifyingandintegratingnewhardwaretechnologieswillallbeattributedtoIT.
Tři volby
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.
Koncept softwarově definovaného úložiště je obrovský. V současné době je součástí SDS mnoho forem ukládání produktů v poli úložiště, jako je virtualizace úložiště, ServerSAN a hyperkonvergovaná architektura (HCI).
1.Ovládací rovina(kontrolní rovina)
Na úrovni řídicího letadla SDS jsou známější:
1)VMwareSPBM(StoragePolicyBase)Management,managementbasedonstoragestrategy);2)OpenStackCinder,CinderisacomponentoftheOpenStackcloudplatformtoprovideblockstorageservices;CindercanaccessmostSANstorageproductsintheindustrythroughaunifiedstoragesoftwareinterface.3)AtypeofstoragemanagementsoftwarerepresentedbyEMCViPR.Thegoalistorealizetheunifiedmanagementofstorageproductsofasinglestoragebrandormultiplestoragebrands,andthepoolingandintegrationofstorageresourcessuchasheterogeneousstoragespace.
2.DataRovina
AttheSDSDataPlanelayer,therearemultiplestorageformsinvolved.
1)BasedonCommodityHardware (založené na komerčním hardwaru), tato část obsahuje dvě hlavní kategorie:
HyperConvergedArchitecture (HCI), měla by být ServerSANSlavnější podmnožiny jsou:VMwareVSANneboEVO:RAIL,EMCScaleIO,Nutanix,Maxta atd.
Nehyper-konvergovaná architektura, tedy nezávislý distribuovaný úložný systém, nejznámějšími jsou DELLFluidCache, HPStorVirtual, RedHatInktankCeph, InspurAS13000 atd.
Tradiční SAN/NAS (externí úložiště), včetně úložiště SAN nebo úložiště NAS
Throughacquisitionorself-development,theSDSabstraction(decoupling),pooling,andautomationphasesaregraduallyrealizedTypicalexamplesincludeHPdecouplingLeftHandfromtheoriginalhardwaretoformtheVSAversionofStorVirtual;NetApplaunchedtheVSAversionofONTAPEdgeVSAofDataONTAP;IBMlaunchedtheXIVsoftwareversionofSpectrumAccelerate;DataCoreSANsymphony;EMClaunchedthevirtualizedversionofVNXvVNXWait.
Cloud/ObjectStorage
UseRESTfulAPIandotherinterfacestoinputandoutputdatawithobjectstorage.TherearecurrentlythreeRESTfulAPIs:AmazonS3,SNIACDMIandOpenStackSWIFT.Themorefamousonesare:EMCAtmos,InspurAS13000andsoon.
Stavební principy
Software-definedstorage(SDS)technologymayprovideameanstomakestoragemoreflexibleandagile,sovirtualstoragevolumescanbecreatedontheflyandworkwitheaseLoadsareassociatedandmovedorconvertedtogetherwithvirtualmachinesbetweenservers.Inaddition,SDSenablesyoutoassociatevalue-addedserviceswithvirtualstoragevolumes(tonameafew,theseservicesmayincludemirroring,replication,thinprovisioning,anddeduplication/compression),sothatstorageapplicationsareastailor-madeTheneedsoftheworkload.Inaddition,agoodSDStechnologyshouldprovidepathmanagementandinterconnectionloadbalancingtomakebetteruseofphysicalstoragedevicesandserversthateitherhostphysicalworkloadsorvirtualizedclients(orboth)Networkandstructuralconnectionsbetween.
Fotbalová branka
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.