RED HAT 认证学习资料：Chapter 2

Chapter2InstallationPreparationCertificationObjectives2.01PlanningtheInstallation2.02IntelCPUHardwareSelectionandConfigurationPackagestoBeInstalled.1PartitioningtheDrive.1HardwareCompatibility.4RAMSizingandCacheIssues.5DiskSubsystems(IDE,EIDE,andSCSI)5IRQSettings.8IRQsandStandardSerialPorts.11SerialandOtherInterfaceMice.11PCCard(PCMCIA)12OneofthestrongpointsofRedHatLinuxisitseasyinstallation.Thereareseveraldifferentmethodsofinstallation,andeachofthemisautomatedtoaconsiderabledegree.However,beforetheactualinstallation,somepreparationisnecessary.CERTIFICATIONOBJECTIVE2.01PlanningtheInstallationBeforeanysoftwarecanbeinstalled,thecomputerhastobeabletorecognizethehardwareitwillbeusing.Theinstallationprocesswillaskyouaboutyourhardware,sohavethisdatareadybeforeyoustart.Youshouldknowthemakeandmodelnumberforeachofthefollowingpiecesofhardware,ifyouhavethem:SCSIcontrollersNetworkinterfacecards(NIC)VideocardsSoundcardsYoumightalsoneedotherinformation,suchasthebaseI/Oaddressandinterruptthateachpieceofhardwareuses.Laterinthischapter,we’lldiscusshardwarecompatibilityforLinux.PackagestoBeInstalledRedHatLinuxcomesconvenientlybundledwithanarrayofpre-configuredsoftwarepackages.Mostlikely,youwillnotneedtoinstallallofthesepackages,andforsecurityreasons(orofficepolicy)itisagoodideanotto.YourbossmightnotappreciatetheofficenetworkbeingusedtoservepersonalWebpagesfromeachemployee'sinstallationofanApacheWebserver.Also,everycomputeronyournetworkdoesn'tneedtoruntheinndnetworknewsservice.Limitthepackagesyouinstalltoonlytheonesyouneed.Ifotherpackagesarerequiredlater,theycanbeinstalledeasilyenoughwiththerpmtool.PartitioningtheDriveItisrecommendedthatyoumakeseveralpartitionswhenpreparingyourharddrivetoinstallLinux.Thisisagoodideaforvariousreasons.First,RedHatLinuxrunstwofilesystems:aLinuxnativefilesystem,andaLinuxswapspace.Second,ifyouwanttoinstallRedHatLinuxandanotheroperatingsystemonthesamecomputer,youwillhavetocreateseparatepartitionsforeach.Thefollowingsectiondiscussesmoreadvantagesofmakingpartitions.StabilityandSecurityTheLinuxnativefilesystemisusuallydividedamongmanyharddrivepartitions.Therecommendedconfigurationisaseparatepartitionforeachofthesedirectories:/,/usr,/tmp,/var,and/homeaswellasseparatepartitionsforcorporatedata,databaseservices,andeventheWebandFTPsitesiftheyareexpectedtobelarge.Partitioningtheharddriveinthismannerkeepssystem,application,anduserfilesisolatedfromeachother.ThisaidsinprotectingthefilespacethattheLinuxkernelandtherestofyourapplicationsuse.Filescannotgrowacrosspartitions.Therefore,anapplicationthatuseshugeamountsofdiskspace,suchasanewsgroupserver,willnotbeabletouseupallofthediskspaceneededbytheLinuxkernel.Anotheradvantageisthatifabadspotdevelopsontheharddrive,itwillbeeasiertorestoreasinglepartitionthantheentiresystem.Stabilityisimproved.Security,also,isimproved.Multiplepartitionsgiveyoutheabilitytomountsomefilesystemsasread-only.Forexample,ifthereisnoreasonforanyuser(evenroot)towritetothe/usrdirectory,mountingthatpartitionasread-onlywillhelpprotectthosefilesfrombeingtamperedwith.Whiletherearemanyincentivestopartitioningyourdiskspace,itmightnotbedesirableforyou.Forsingle-usersystems,orwherediskspaceisscarce,asimplerfilesystemlayoutwouldbecalledfor.Forexample,ifthe/vardirectoryisonitsownpartitionof300MB,only100MBmightbeused.Thatmakes200MBofwasteddiskspace.AsofRH7.x,boththewebandftpdocumentrootshavebeenaddedto/var.Thesemayaddadditionaldiskspacerequirementsfor/var.Currently,thereisnoeasywaytoresizeLinuxpartitions.Therefore,alotofcarefulconsiderationshouldbeputintowhetheryouwanttopartitionyourdiskspace,andhowtodoit.HowMuchSpaceIsRequired?YoushouldsizeyourLinuxpartitionsaccordingtoyourneedsandthefunctionofthecomputer.Forexample,amailserverwillrequiremorespaceforthe/vardirectorybecausethemailspoolresidesin/var/spool/mail.Youmayevenwanttocreateaseparatepartitionjusttoaccommodate/var/spool/mail.AsofRH7.x,boththewebandftpdocumentrootshavebeenaddedto/var.Thesemayaddadditionaldiskspacerequirementsfor/var.Generally,therootpartitionisarelativelymodestsize,andtherestissplitupdependingonsystemuse.Example:FileServerIftheLinuxsystemyouareinstallingistobeafileserver,thenyourfilesystemcouldlooksomethinglikeTable2-1.FilesystemSize(MB)Mountedon/dev/sda1400//dev/sda52000/var/dev/sda6300/usr/dev/sda760Swapspace/dev/sda81000/home/dev/sda93000/home/sharedTable1:ExampleDiskPartitionSchemeforaLinuxFileServerThe/usrfilesystemislargeenoughtohaveSambainstalled,aswellasX11,ifthatisdesired.Mostofthediskspacehasbeenallocatedto/var,forthelogfiles,FTPandHTTPDservices,to/home,forusers'ownfiles,andto/home/shared,forcommonfiles.Ofcourse,thisisonlyanexample.Theamountofdiskspaceyouallocateforfilesharingwilldependonfactorssuchasthenumberofusersandthetypeoffilestheyworkon.LinuxSwapSpaceNormally,Linuxcanuseamaximum4GBofswapspace.This4GBcanbespreadoveramaximumofeightpartitions.Notethateachswappartitionisrestrictedtoamaximumof2GB.Thereisnoauthoritativeformulafordecidinghowmuchswapspaceshouldbemade,butyoucanmakeanestimatebasedonthetypicalUNIXruleofthumb,sw