Virtuaalinen isäntä

Määritelmä

Virtualhosting,alsocalled"websitespace",istodivideaphysicalserverrunningontheInternetintomultiple"virtual"servers.Virtualhosttechnologyhasgreatlypromotedtheapplicationandpopularizationofnetworktechnology.Atthesametime,therentalserviceofvirtualhostshasbecomeaneweconomicformintheInternetage.

Tausta

Therearenearly100millioncomputersinterconnectedontheInternet.Nomatterwhattypeofcomputertheyare,whatoperatingsystemtheyrun,andwhatsoftwaretheyuse,theycanbeclassifiedintotwocategories:customersMachinesandservers.

  • Client:Theclientisamachinethataccessesotherhosts.WhenaccessingtheInternetthroughanISP(InternetServiceProvider),theclientisassignedatemporaryIPaddress.UsingthistemporaryIPaddress,theclientcanobtaininformationontheInternet.Afterthenetworkisdisconnected,theclientThemachinewasseparatedfromtheInternet,andtheIPaddresswastakenback.

  • Server:Aserverisacomputerthathashighcomputingpowerandcanbeusedbymultipleusers.Itisusuallycalledahost.Therearemanydifferencesbetweentheserverandtheclient.Forexample,theclientusuallyonlyservesoneuseratatime.Theclientisusedbytheuserthroughtheterminal,andtheserverisusedbytheclientuserthroughthenetwork.Comparedwiththeclient,theserverneedstoworkcontinuouslyinanenvironmentof7×24hours.ThismeansthattheserverneedsmorestabilitytechnologyRAS(Reliability,AvailabilityandServiceability,reliability,availability,applicability),suchassupportingtheuseofECC(ErrorCheckandCorrection)memory.

Tekniset ominaisuudet

VirtualhostingtechnologyisatechnologyusedbyInternetserverstosaveserverhardwarecosts.VirtualhostingtechnologyismainlyusedinHTTP(HypertextTransferProtocol).,HypertextTransferProtocol)service,whichlogicallydividesacertainoralloftheservicecontentofaserverintomultipleserviceunits,whichareexternallyrepresentedasmultipleservers,soastomakefulluseofserverhardwareresources.

Virtualhostusesspecialsoftwareandhardwaretechnologytodividearealphysicalserverhostintomultiplelogicalstorageunits.Eachlogicalunithasnophysicalentity,buteachlogicalunitcanworkonthenetworklikearealphysicalhost,withaseparateIPaddress(orsharedIPaddress),anindependentdomainname,andacompleteInternetserver(supportWWW,FTP,E-mail,etc.)functions.

Thekeytechnologyofvirtualhostingisthatevenifdifferentserverprogramsopenedformultipleusersarerunningonthesamehardwareandthesameoperatingsystem,theydonotinterferewitheachother.Eachuserhashisownpartofthesystemresources(IPaddress,documentstoragespace,memory,CPU,etc.).Eachvirtualhostiscompletelyindependent.Fromtheoutside,eachvirtualhostandasinglehostbehaveexactlythesame.Therefore,thisvirtualizedlogicalhostisvividlycalleda"virtualhost".

Edut

Halpa

Comparedwiththepurchaseofanindependentserver,thecostofwebsiteconstructionisgreatlyreduced,whichprovidesgreatconvenienceforthepopularizationofsmallandmedium-sizedwebsites.

Thevirtualhostsarecompletelyindependent.Fromtheoutsideworld,eachvirtualhostisexactlythesameasanindependenthost.Sincemultiplevirtualhostssharetheresourcesofarealhost,thehardwarecosts,networkmaintenancecosts,andcommunicationlinecoststhateachvirtualhostuserbearsaregreatlyreduced.

Manycompaniesusethismethodtobuildwebsites,whichnotonlygreatlysavesthecostofbuyingmachinesandrentingdedicatedlines,butalsothewebsiteservermanagementissimple.Securitymeasuressuchassoftwareconfiguration,anti-virus,andanti-attackarealldonebyprofessionalTheserviceproviderprovides,whichgreatlysimplifiesthecomplexityofservermanagement;atthesametime,thereisnoneedtoworryaboutthetechnicalproblemsofusingandmaintainingtheserver,andthereisnoneedtohirespecializedmanagementpersonnel.

Parantaa tehokkuutta

Intheinitialstageofwebsiteconstruction,ittakesalongtimetoinstalltheoperatingsystemandapplicationsoftwarefromthepurchaseofaserver,whilerentingavirtualhostusuallyonlytakesafewminutestoactivate.Becausethemajorregistereddomainnamequeryserviceprovidershaverealizedthee-commerceoftheentirebusinessprocess,chooseavirtualhostthatsuitsyourneeds,andyoucanopenitimmediatelyafteronlinepayment.

TheemergenceofvirtualhosttechnologyisamajorcontributiontothedevelopmentofInternettechnologyandnetwork.Sincemultiplevirtualhostssharetheresourcesofarealhost,theutilizationrateofserversandcommunicationlinesisgreatlyincreased,makingoneMultiplenetworkIPaddressescanbeconfiguredonaserverwithoutconflict,whichmeansthatpeoplecanusevirtualhoststobuildseveralsiteswithseparatedomainnamesononeserver,insteadofhavingtopurchaseseparatesitestobuildasite.Serversanddedicatedlinesforapplicationwithhugesumsofmoneyareusedasnetworkinformationoutlets.

Haitat

Toiminnan rajoitukset

Somefunctionsarerestrictedbyserviceproviders,suchasforumprogramsthatmayconsumesystemresources,trafficstatisticsfunctions,etc.Websitedesignneedstoconsiderthefunctionalsupportprovidedbytheserviceprovider,suchasdatabasetype,operatingsystem,etc.Generally,virtualhostsdonothaveaseparateIPaddressinordertoreducecosts,thatis,IPaddressescannotdirectlyaccesswebsites(becausetherearemultiplewebsitescorrespondingtothesameIPaddress)

Kulkunopeus ja liikennerajoitukset

Differentvirtualhostsonaserverareindependentandmanagedbyusers.However,aserverhostcanonlysupportacertainnumberofvirtualhosts.Whenthisnumberisexceeded,userswillexperienceasharpdropinperformance.

Theaccessspeedofsomevirtualhostwebsitesistooslow.Thismaybecausedbythehostingproviderrentingahosttoalargenumberofwebsites,orserverconfigurationandotherreasons.ThissituationwebsiteIfyoucan’tsolveitbyyourself,itwillhaveanadverseeffectonthenormalvisitofthewebsite;

Someserviceprovidershavecertainrestrictionsonwebsitetraffic,sothatnormalvisitswillnotbepossiblewhenthewebsitehasalargeamountofvisits.

Huono autonomia

Thevirtualhostcannotbeoperatedbythecustomertoinstallsoftwareandremotedesktopatwill.

Tarkoitus

Kätevä hallinta

Allvirtualhostsareinthesamehost,sotheycansharethesameconfigurationsettings,therebysavingmanagementmanpowerAndcost.

Paranna suorituskykyä

Virtualhostsinthesamehostcanshareeachother'sassembly(ProcessPool),sotheresponsetimetotheclientcanbeshortened.

Kustannusten vähentäminen

Virtualhostingallowstheresourcesofasingleservertobeusedmoreeffectively,includingmemory,storagespaceorprocessorresources.BecausetheresourcesrequiredtoserveasingleURLareusuallyquitesmallfortheentireserver,thisallowstheserver'sresourcestobeusedmoreeffectively.

Multiplevirtualserverscanbesetuponthesamephysicalserverthroughsoftware,andeachvirtualservercanprovideallthefunctionsoftheserver,sorelativelyspeaking,thecostofeachvirtualserverhasacertaindegreereduce.

Toteutustyyppi

Käyttöönottomenetelmiä on kolme: URL-nimivastaavuus (nimipohjainen), IP-osoitevastaavuus (IP-pohjainen) ja porttinumerovastaavuus (porttipohjainen).

URL-osoitteen vastaavuus (nimipohjainen)

URL-osoitteen vastaavuus (nimipohjainen)istodeterminethecorrespondingservicebyidentifyingtheURLprovidedbytheclient.ThismethodEffectivelyreducetheoccupationoftheIPaddress,butthedisadvantageisthatitmustrelyonthesupportoftheDNSnamemappingservice.Ifthenamemappingserviceisinterrupted,theservicecorrespondingtothenamewillalsobeunavailable.

IP-osoitteen vastaavuus (IP-pohjainen)

IP-osoitteen vastaavuus (IP-pohjainen)referstothesameserver,throughthesameconfigurationsettings,differentIPtomanageMultipleservices.

Porttipohjainen kirjeenvaihto (Porttipohjainen)

ItissimilartoIPaddresscorrespondence,butunderthesameIP,differentPortportnumbersareusedtodistinguishdifferentservices.Inordertoquicklycreatemultiplevirtualhosts.Forexample:

  • 192.168.0.1:80

  • 192.168.0.1:8080

  • 192.168.0.1:8888

However,mostoftheseapplicationsareusedinprivateorexperimentalservicesbecauseuserscannotusethedefaultportnumber(forexampleThedefaultportnumberofthewebserviceis80)tousetheprovidedservice,unlesstheuserknowstheportnumberforprovidingtheservice.

Valitse virtuaalinen isäntä

  • isännän laitteistopalvelut

  • WhatthevirtualhostproviderownsThevirtualhostcomputerroom,whatsizedatacenterisit,whetherthereisenoughbandwidthforthecomputerroomline,andwhetherthespeedofthevirtualhostwebsiteconnectionmeetsthetrafficbandwidthofallhisvirtualhostcustomersatthesametime.

  • Kuinka monta verkkosivustoa asetetaan virtuaalipalvelimelle

  • Usuallyavirtualhostcanhosthundredstothousandsofwebsites,ifThemorewebsitesthereare,themorepeoplesharethesameserver;incomparison,resourcesaretighter.Generallyrelatedtothemachine'sCPU,memory,etc.IISisgenerally10000/numberofconnectionsperserver.

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