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.