The Official Red Hat Linux System Administration Primer (Red Hat Linux 8)

140 Pages·0.767 MB·English

by  RedHat

Red Hat Linux 8.0
The Of(cid:2)cial Red Hat Linux
System Administration Primer
RedHatLinux8.0:TheOf(cid:2)cialRedHatLinuxSystemAdministrationPrimer
Copyright'2002byRedHat,Inc.
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Table of Contents
Introduction.........................................................................................................................................v
1.DocumentConventions.........................................................................................................v
2.MoretoCome....................................................................................................................viii
2.1.SendinYourFeedback.......................................................................................viii
3.SignUpforSupport...........................................................................................................viii
I.BackgroundInformation...............................................................................................................ix
1.ThePhilosophyofSystemAdministration.........................................................................11
1.1.AutomateEverything...........................................................................................11
1.2.DocumentEverything..........................................................................................12
1.3.CommunicateasMuchasPossible......................................................................13
1.4.KnowYourResources..........................................................................................15
1.5.KnowYourUsers.................................................................................................15
1.6.KnowYourBusiness............................................................................................16
1.7.SecurityCannotbeanAfterthought....................................................................16
1.8.PlanAhead...........................................................................................................17
1.9.ExpecttheUnexpected........................................................................................17
1.10.InConclusion...................................................................................................17
II.ResourceManagement................................................................................................................19
2.ResourceMonitoring..........................................................................................................21
2.1.BasicConcepts.....................................................................................................21
2.2.SystemPerformanceMonitoring.........................................................................21
2.3.MonitoringSystemCapacity...............................................................................22
2.4.ResourceMonitoringTools..................................................................................22
3.BandwidthandProcessingPower.......................................................................................27
3.1.Bandwidth............................................................................................................27
3.2.ProcessingPower.................................................................................................30
4.PhysicalandVirtualMemory.............................................................................................35
4.1.StorageAccessPatterns.......................................................................................35
4.2.TheStorageSpectrum..........................................................................................35
4.3.BasicVirtualMemoryConcepts..........................................................................39
4.4.VirtualMemory:theDetails................................................................................40
4.5.VirtualMemoryPerformanceImplications.........................................................42
5.ManagingStorage...............................................................................................................45
5.1.DeviceNamingConventions...............................................................................45
5.2.Partitions..............................................................................................................47
5.3.FileSystemBasics...............................................................................................49
5.4.Adding/RemovingStorage...................................................................................54
5.5.RAID-BasedStorage...........................................................................................60
5.6.MonitoringDiskSpace........................................................................................68
5.7.ImplementingDiskQuotas..................................................................................68
5.8.AWordAboutBackups.....................................................................................73
III.GettingItDone...........................................................................................................................75
6.ManagingAccountsandGroups.........................................................................................77
6.1.UserAccounts,Groups,andPermissions............................................................77
6.2.FilesControllingUserAccountsandGroups......................................................78
6.3.UserAccountandGroupApplications................................................................81
6.4.TheProcessofCreatingUserAccounts..............................................................83
6.5.ManagingUserResources...................................................................................85
7.PrintersandPrinting...........................................................................................................89
7.1.TypesofPrinters..................................................................................................89
7.2.ImpactPrinters.....................................................................................................90
7.3.InkjetPrinters.......................................................................................................91
7.4.LaserPrinters.......................................................................................................92
7.5.OtherPrinterTypes..............................................................................................93
7.6.PrinterLanguagesandTechnologies...................................................................93
7.7.NetworkedVersusLocalPrinters.........................................................................94
7.8.PrinterCon(cid:2)gurationandSetup...........................................................................94
7.9.PrinterSharingandAccessControl.....................................................................96
7.10.AdditionalResources.........................................................................................98
IV.ThinkingAbouttheUnthinkable............................................................................................101
8.PlanningforDisaster.........................................................................................................103
8.1.TypesofDisasters..............................................................................................103
8.2.Backups..............................................................................................................119
8.3.DisasterRecovery..............................................................................................128
Index.................................................................................................................................................133
Colophon..........................................................................................................................................139
Introduction
WelcometotheOf(cid:2)cialRedHatLinuxSystemAdministrationPrimer.
TheOf(cid:2)cialRedHatLinuxSystemAdministrationPrimercontainsintroductoryinformationfornew
RedHatLinuxsystemadministrators.Itwillnotteachyouhowtoperformaparticulartask;rather,it
willprovideyouwiththebackgroundknowledgethatmoreexperiencedsystemadministratorshave
learnedovertime.
ThisguideassumesyouhavealimitedamountofexperienceasaLinuxuser,butnoLinuxsystem
administration experience. If you are completely new to Linux in general (and Red Hat Linux in
particular),youshouldstartbyreadingtheOf(cid:2)cialRedHatLinuxGettingStartedGuide.
MoreexperiencedsystemadministratorsshouldskimtheOf(cid:2)cialRedHatLinuxSystemAdministra-
tionPrimerforoverallconcepts,andthenconcentrateonusingtheOf(cid:2)cialRedHatLinuxCustomiza-
tionGuideforassistanceinperformingspeci(cid:2)ctasksinaRedHatLinuxenvironment.Administra-
torsrequiringmorein-depth,factualinformationshouldrefertotheOf(cid:2)cialRedHatLinuxReference
Guide.
Note
Althoughthismanualre(cid:3)ectsthemostcurrentinformationpossible,youshouldreadtheRedHat
LinuxReleaseNotesforinformation thatmaynothavebeenavailablepriortoourdocumentation
being(cid:2)nalized.TheycanbefoundontheRedHatLinuxCD#1andonlineat:
http://www.redhat.com/docs/manuals/linux
1.DocumentConventions
Whenyoureadthismanual,youwillseethatcertainwordsarerepresentedindifferentfonts,type-
faces,sizes,andweights.Thishighlightingissystematic;differentwordsarerepresentedinthesame
styletoindicatetheirinclusioninaspeci(cid:2)ccategory.Thetypesofwordsthatarerepresentedthisway
includethefollowing:
command
Linuxcommands(andotheroperatingsystemcommands,whenused)arerepresentedthisway.
Thisstyleshouldindicate toyouthat youcan typethewordorphrase onthecommandline
andpress[Enter]toinvokeacommand.Sometimesacommandcontainswordsthatwouldbe
displayedinadifferentstyleontheirown(suchas(cid:2)lenames).Inthesecases,theyareconsidered
tobepartofthecommand,sotheentirephrasewillbedisplayedasacommand.Forexample:
Usethecat testfilecommandtoviewthecontentsofa(cid:2)le,namedtestfile,inthecurrent
workingdirectory.
filename
Filenames,directorynames,paths,andRPMpackagenamesarerepresentedthisway.Thisstyle
shouldindicate that aparticular (cid:2)leordirectory existsbythat name onyourRed Hat Linux
system.Examples:
The.bashrc(cid:2)leinyourhomedirectorycontainsbashshellde(cid:2)nitionsandaliasesforyourown
use.
The/etc/fstab(cid:2)lecontainsinformationaboutdifferentsystemdevicesand(cid:2)lesystems.
InstallthewebalizerRPMifyouwanttouseaWebserverlog(cid:2)leanalysisprogram.
vi Introduction
application
Thisstyleshouldindicatetoyouthattheprogramnamedisanend-userapplication(asopposed
tosystemsoftware).Forexample:
UseMozillatobrowsetheWeb.
[key]
Akeyonthekeyboardisshowninthisstyle.Forexample:
Touse[Tab]completion,typeinacharacter andthenpressthe[Tab]key.Yourterminalwill
displaythelistof(cid:2)lesinthedirectorythatstartwiththatletter.
[key]-[combination]
Acombinationofkeystrokesisrepresentedinthisway.Forexample:
The[Ctrl]-[Alt]-[Backspace]keycombinationwillexityourgraphicalsessionandreturnyouto
thegraphicalloginscreenortheconsole.
textfoundonaGUIinterface
Atitle,word,orphrasefoundonaGUIinterfacescreenorwindowwillbeshowninthisstyle.
Whenyouseetextshowninthisstyle,itisbeingusedtoidentifyaparticularGUIscreenoran
elementonaGUIscreen(suchastextassociatedwithacheckboxor(cid:2)eld).Example:
SelecttheRequirePasswordcheckboxifyouwouldlikeyourscreensavertorequireapassword
beforestopping.
toplevelofamenuonaGUIscreenorwindow
Whenyouseeawordinthisstyle,itindicatesthatthewordisthetoplevelofapulldownmenu.
IfyouclickonthewordontheGUIscreen,therestofthemenushouldappear.Forexample:
UnderFileonaGNOMEterminal,youwillseetheNewTaboptionthatallowsyoutoopen
multipleshellpromptsinthesamewindow.
IfyouneedtotypeinasequenceofcommandsfromaGUImenu,theywillbeshownlikethe
followingexample:
GotoMainMenuButton(onthePanel)=>Programming=>EmacstostarttheEmacstext
editor.
buttononaGUIscreenorwindow
ThisstyleindicatesthatthetextwillbefoundonaclickablebuttononaGUIscreen.Forexample:
ClickontheBackbuttontoreturntothewebpageyoulastviewed.
computer output
Whenyouseetextinthisstyle,itindicatestextdisplayedbythecomputeronthecommandline.
Youwillseeresponsestocommandsyoutypedin,errormessages,andinteractivepromptsfor
yourinputduringscriptsorprogramsshownthisway.Forexample:
Usethelscommandtodisplaythecontentsofadirectory:
$ ls
Desktop about.html logs paulwesterberg.png
Mail backupfiles mail reports
Theoutputreturnedinresponsetothecommand(inthiscase,thecontentsofthedirectory)is
showninthisstyle.
Introduction vii
prompt
Aprompt,whichisacomputer’swayofsignifyingthatitisreadyforyoutoinputsomething,
willbeshowninthisstyle.Examples:
$
#
[stephen@maturin stephen]$
leopard login:
user input
Textthattheuserhastotype,eitheronthecommandline,orintoatextboxonaGUIscreen,is
displayedinthisstyle.Inthefollowingexample,textisdisplayedinthisstyle:
Tobootyoursystemintothetextbasedinstallationprogram,youwillneedtotypeinthetext
commandattheboot:prompt.
Additionally,weuseseveraldifferentstrategiestodrawyourattentiontocertainpiecesofinformation.
Inorderofhowcritical theinformationistoyoursystem,theseitemswillbemarkedasnote,tip,
important,caution,orawarning.Forexample:
Note
RememberthatLinuxiscasesensitive.Inotherwords,aroseisnotaROSEisnotarOsE.
Tip
The directory /usr/share/doc contains additional documentation for packages installed on your
system.
Important
IfyoumodifytheDHCPcon(cid:2)guration(cid:2)le,thechangeswillnottakeeffectuntilyourestarttheDHCP
daemon.
Caution
Donotperformroutinetasksasroot(cid:151)usearegularuseraccountunlessyouneedtousetheroot
accountforsystemadministrationtasks.
viii Introduction
Warning
Ifyouchoosenottopartitionmanually,aserverinstallationwillremoveallexistingpartitionsonall
installedharddrives.Donotchoosethisinstallationclassunlessyouaresureyouhavenodatayou
needtosave.
2.MoretoCome
TheOf(cid:2)cialRedHatLinuxSystemAdministrationPrimerispartofRedHat’sgrowingcommitment
toprovideusefulandtimelysupporttoRedHatLinuxusers.AsnewreleasesofRedHatLinuxare
madeavailable,wemakeeveryefforttoincludebothnewandimproveddocumentationforyou.
2.1.SendinYourFeedback
IfyouspotatypointheOf(cid:2)cialRedHatLinuxSystemAdministrationPrimer,orifyouhavethought
of away to make this manual better, wewould love to hear from you.Please submit a report in
Bugzilla(http://www.redhat.com/bugzilla)againstthecomponentrhl-sap.
Besuretomentionthemanual’sidenti(cid:2)er:
rhl-sap(EN)-8.0-Print-RHI (2002-10-01T17:12-0400)
Ifyoumentionthismanual’sidenti(cid:2)er,wewillknowexactlywhichversionoftheguideyouhave.
Ifyouhaveasuggestionforimprovingthedocumentation,trytobeasspeci(cid:2)caspossible.Ifyou
havefoundanerror,pleaseincludethesectionnumberandsomeofthesurroundingtextsowecan
(cid:2)nditeasily.
3.SignUpforSupport
Ifyouhaveanof(cid:2)cialeditionofRedHatLinux8.0,pleaseremembertosignupforthebene(cid:2)tsyou
areentitledtoasaRedHatcustomer.
Youwillbeentitledtoanyorallofthefollowingbene(cid:2)ts,dependingupontheOf(cid:2)cialRedHatLinux
productyoupurchased:
(cid:149) Of(cid:2)cialRedHatsupport(cid:151)GethelpwithyourinstallationquestionsfromRedHat,Inc.’ssupport
team.
(cid:149) RedHatNetwork(cid:151)Easilyupdateyourpackagesandreceivesecuritynoticesthatarecustomized
foryoursystem.Gotohttp://rhn.redhat.comformoredetails.
(cid:149) UndertheBrim:TheOf(cid:2)cialRedHatE-Newsletter(cid:151)Everymonth,getthelatestnewsandproduct
informationdirectlyfromRedHat.
Tosignup,gotohttp://www.redhat.com/apps/activate/.Youwill(cid:2)ndyourProductIDonablack,red,
andwhitecardinyourOf(cid:2)cialRedHatLinuxbox.
ToreadmoreabouttechnicalsupportforOf(cid:2)cialRedHatLinux,refertotheGettingTechnicalSup-
portAppendixintheOf(cid:2)cialRedHatLinuxInstallationGuide.
Goodluck,andthankyouforchoosingRedHatLinux!
TheRedHatDocumentationTeam
Background Information