毕业设计英文外文翻译虚拟服务器Word文件下载.docx
《毕业设计英文外文翻译虚拟服务器Word文件下载.docx》由会员分享，可在线阅读，更多相关《毕业设计英文外文翻译虚拟服务器Word文件下载.docx（5页珍藏版）》请在冰豆网上搜索。
Asarephysicalservers,avirtualPCisuselessuntilyouinstallanoperatingsystemonit.Theoperatingsystemsthatyouinstallonyourvirtualhostsarecalledguests.InstallingaguestOScanbeaseasyasbootingfromtheOS’sinstallationCD.It’sjustlikeinstallinganOSonaPC,andingeneral,ifyouwonderhowvirtualizationwillbehave,that’stheanswer:
JustlikeaPC.
Infact,inanall-Windowsenvironment,it’seasytoloseyourplace:
AreyoulookingatyourWindowshostOSoratoneofthefourWindowsguestOSesyoujustinstalled?
Youmightgetconfused,butyourguestOSesandtheirapplicationsneverdo.EachguestOSbelievesithasthewholemachinetoitself.And,inasense,itdoes.
Software-basedhardware
Operatingsystemsandapplicationsrunningonvirtualserversdon’thavedirectcontroloverresourcessuchasmemory,harddrives,andnetworkports.Instead,theVMthatsitsbeneaththeOSandapplicationsinterceptsrequestsforinteractionwithhardwareandhandlesthemasitseesfit.
Therealmindblowerthatturnsthistechnologyintosomethingclosetomagicisthataworld-classvirtualizationsolutionsuchasVMwareESXServercansynthesizeanentirehardwareconfigurationthathaslittleresemblancetotheunderlyinghardware.Forexample,thehostmightsimulatetheinitializationprocessofaSCSIcontrollertothelastdetail,convincingtheguestOSthatthisinitializationisbeingperformedevenwhennophysicalSCSIcontrollerexists.ItcanmakeIDEdriveslooklikeSCSIdrives,convertnetworksharesintolocallyattachedstorage,turnoneEthernetadapterintoseveral,andcreategatewaysbetweenolderoperatingsystemsandunsupportedmodernhardwaresuchasFibreChanneladapters.Youbuildyourownserversthatpreciselyfittheneedsofyourapplications,butyouuseamouseinsteadofascrewdriver.
InstallingtheOSandsoftwareontoaphysicalPCservereverytimeyouneedonecanbetedious.Fortunately,withvirtualizationyoudon’thaveto.Afteryou’vetunedavirtualizedhardwareconfigurationpreciselytoyourliking,youcansavethatserver’sdiskimagetoafileanduseitasatemplateforotherguestsystems.Inpractice,thisisadelight.Youcanbackupavirtualserverbycopyingthefile.Youcancreateanewserverbyduplicatingthefile—copyingWindowsrequiresreactivationandanappropriatelicense—ormoveanexistingservertodifferentphysicalhardware.
Virtualizedserversdoallthegoodandbadthingsregularserversdo.Theybootup,powerdown,suspend,hang,andevencrash.IfaguestOSoradevicedriveritusesisbuggy,thevirtualPCwillcrater.Butnotthephysicalcomputer,andthat’skey.
IfyourOScrashesoranapplicationhangs,orevenifyouinstallasoftwarefixthatrequiresareboot,nothinghappenstothehardware.Onevirtualmachinecanfailovertoanotherinapurelyvirtualsenseorinawaythat’sclosertotherealthing.Evenifcertainhardwaredeviceshavemalfunctioned,solongasthefail-overtargetisconfiguredtouseasecondarynetworkadapterandanalternatepathtostorage,thefail-overwillworkexactlyasitwouldifthevirtualPCswerephysicalPCs.
Inmostcases,anenterprisemanagementsystemwillmonitorandreacttoavirtualfail-overasifitweretherealthing.SolutionssuchasHPOpenViewseeandinteractwithvirtualserversthesamewaytheydowithphysicalones.Thereportedconfigurationsoftheserverswillchangeafterthey’revirtualized,butit’sentirelylikelythattheday-to-daymanagementofyourshopwillexperiencelittlechange.
Whybuildthesuppositionalleadplane？
Internetbecomesthefocalpointthatthebusinessfamilyfixeseyesongradually,indevelopmentoftechnologyswiftandviolenttoday,enterprise'
sinformationizealreadybecomingimportantmarketcompetitionDuan.Oneoftrendmarketplace,trendinternationalizationorthenecessaryconditionkeepinghomemarketwon'
tshrinkistomustowntheunimpededmoderntimesinternationalconnectionmeans:
Selfdomainname,selfhostpage,selfelectronmailbox,selfpropagatingposition.Where,conditionnowtobememberofdisregardingyourenterprisehow,thatharddiskspacerentsout,thesuppositionalleadplaneofnetworkservesaserverusesallthesebecomesreality!
Thenetworkbecomesaimportantwayofmarketingandsalesalreadygradually,thatanyenterprisecarriesoutupperElectronicCommerceofnetallisapieceofveryprudentthingbut,becauseofitsthrowingintoonmanpowerandmaterialresourcesisverybig.Whennotsatisfyingsufficientrequirmentsenterprise,buildingatrialsupposingaleadplanetocarryoutElectronic
Commercefirstonthenetworkisverynecessary.Letthespecialfieldcompanycometobearthesystematicupkeepandmanage,feasibleenterprisecansavemoremanpowerandcostcomposeotherbusiness.Youhaveownedthesuppositionalleadplane（websiteserver）havingfoundedselfrightawayhavingcaughtwithanetelectronadvertisementoveralongperiodoftime.）
Inaddition,mostvirtualizationsystemsbundlesolution-specificmanagementsoftware,allowinganadministratortositatacentralconsoleandmanipulateallthevirtualserversinanenterprise.It’squiteaneye-openertoswapoutavirtualEthernetcardwithoutevertouchingthehardware.
Avirtualizationsolution’smanagementconsolegivesyouadegreeofcontroloveryourvirtualPCsthatsurpasseswhatadministratorscandowithtraditionaltools.Fromacentrallocation,youcanbootandshutdownvirtualPCsasneeded.It’salsopossibletopausethem,whichharmlesslyfreezesthemintheircurrentstate,orhibernatethem,puttingtheminadeepfreezebysavingtheirstatetoafileondisk.Byoverwritingthediskfile,youcanrestorePCsfromabacked-upstateandrollbackchangesthatrenderedtheguestinoperable,allfromaterminalsession.
Inenvironmentswithamixofoperatingsystems——acommonconditionthatturnsevensimpleconsolidationintoamessyaffair——onesolutionwouldbetohosteachOSinitsownVM.Forexample,onaPCserverrunningoneofVMware’svirtualizationsolutions,youcanrunanycombinationofWindows2003Server,Windows2000,WindowsNT4.0,variousflavorsofLinux,andFreeBSD.YoucanevenuseVMstohostdifferentversionsofthesameOS.LinuxsoftwareisinfamousfordependenceonspecificversionsandvendordistributionsofLinux.VirtualizationistheonlywaytorunapplicationsdesignedforRedHat7.2andSuse9.0simultaneouslyonasingleserver.
Virtualizationismagnificentstuff,butitdoesn’tcureallills.YoucannevercreateavirtualPCthatoutperformsthephysicalsystemunderneath.Youwilllearnmuchaboutyourapplications’systemrequirementsfrommovingthemtoavirtualenvironment.They’lllikelysurpriseyou,eitherwithhowlittleoftheoriginalservertheyused——that’sthetypicalcase——orhowpiggishtheyare.Ifnecessary,youcanthrottlethenastyonesdown.
Andwhileoneofthegreatbenefitsofvirtualizationissecurity——it’shardtoaccomplishmuchbycrackingasystemthatdoesn’texist——avirtualizedPCcanstillbecompromised.Fortunately,thecureistooverwritethevirtualPC’sdiskimagewithonethat’sknowntobeclean,butmanagingvirtualserversstillrequiresvigilance.
Ultimately,hardwareconsolidationisonlyonereasontooptforservervirtualization,andithaswideappeal.Still,dependingoneachdepartment’suniqueneeds,ITmanagersaresuretofindinnumerablewaysthatvirtualizationcanbenefityourenterprise.（TheEnd）
虚拟服务器
服务器的虚拟化是少有的几种技术之一，它们听上去好的好像很不真实，但实际上是真的。
虚拟服务器在早期的用途是减少使用率不足的服务器硬件，将处理任务集中到数量更少的机器上。
自这些早期应用以来，现在已经发展成一种多目的的解决方案，实现更高的可靠性、更好的管理、以及成为企业数据中心管理员不可或缺的工具。
按照非常简化的定义，虚拟服务器仅仅是利用单独的软件来模拟计算机的独立行为和能力。
虚拟化实质上是一个很简单的术语，服务器虚拟化。
软件底部的堆栈是直接安装在服务器硬件上的普通的操作系统。
其上是处理重新定向和仿真的虚拟层，而重新定向和仿真构成了虚拟计算机。
这底部的两层合起来被叫做宿主机。
宿主机提供大家熟悉的PC机BIOSROM的全部工作，按照用户的选择，利用改变用户定义的配制而生出很多独立的PC机。
作为物理的服务器，一个虚拟的PC机在没有安装操作系统之前是不可以使用的。
安装在虚拟宿主机上的操作系统称作OS。
安装客操作系统OS非常简便，只需从OS的安装光盘上引导过来。
这和PC机上安装OS没有什么两样。
一般来说，如果你对虚拟化是如何运转的感到惊奇，那么这就是答案：
就像一台PC机。
事实上，在一个全Windows环境下，你很容易迷失了方向：
是在看Windows宿主机OS，还是在看刚刚安装的四个Windows客OS中的一个？
你自己可能产生困惑，但你的寄宿OS及其应用程序是从来不会弄错的。
每个寄宿OS认为它拥有整个机器。
在某种意义上，它是拥有整个机器。
基于软件的硬件
连续运行在虚拟服务器上的操作系统和应用程序不直接控制内存、硬盘和网络端口等资源，取而代之的是位于OS和应用程序之间的VM（虚拟机）截取与硬件交互的请求并在认为合适时对它们进行处理。
真正将此技术变成接近于魔术的是VMware公司的ESXServer等世界级的虚拟化解决方案，这类解决方案能合成整个硬件的配置，而它与基础的硬件几乎没有关系。
例如，宿主机可以最详细地模拟SCSI控制器的初始化过程，让客OS相信即使不存在物理的SCSI控制器时初始化也在被执行。
它能使IDE磁盘机看上像SCSI磁盘机，能将网络共享的磁盘机转换成装在本机内的存储设备，将一个以太网卡变成几个网卡，并能在较老式的操作系统和它不支持的新式硬件（如光通道卡）之间生成网关。
你可以建立完全适合应用程序需要的属于你自己的服务器，这时你用的是鼠标而不是用改锥。
在每次需要时把OS和软件装到物理的PC服务器是很烦人的。
幸亏有了虚拟化你就不必这么做。
在完全按你的
升级会员 