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What’s neW in Red hat enteRpRise Linux 5 Table of contentsOverview............................................................................................................................................2
RedHatEnterpriseLinux5benefitssummary........................................................................2
Simplified Packaging.......................................................................................................................2
An open source infrastructure for stable and mature commercial deployments............3
Virtualization..................................................................................................................................3
SecurityEnhancements...............................................................................................................4
Auditing...........................................................................................................................................5
AutoFS.............................................................................................................................................5
Samba..............................................................................................................................................6
FS-Cache......................................................................................................................................... 6
NFS...................................................................................................................................................6
GlobalFileSystem,LogicalVolumeManagerandDistributedLockManager...................6
ApplicationandVirtualMachineFailover..................................................................................7
EnhancedStorageCapabilities................................................................................................... 7
Red Hat Network........................................................................................................................... 7
Desktop & Productivity..................................................................................................................8
GCC4.1 Compiler............................................................................................................................8
Systemtap and Frysk.................................................................................................................... 8
Network Manager.......................................................................................................................... 8
Graphic Subsytem.........................................................................................................................9
Hardware management................................................................................................................9
Smart Card Login..........................................................................................................................9
Stateless Linux............................................................................................................................. 10
Options...........................................................................................................................................10
Performance & Scalability........................................................................................................... 10
Multi-Path I/O.................................................................................................................................11
Learn more about Red Hat Enterprise Linux 5...........................................................................................11
www.redhat.com
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OveRvieW
In2002RedHatintroducedtheworld’sfirstcommerciallyfocusedopensourceoperating
system–RedHat®EnterpriseLinux®.Itrapidlyestablisheditselfasaleadingoperating
systemplatform,deliveringanunmatchedcombinationofquality,security,performanceand
features.CustomersuseRedHatEnterpriseLinuxforahugevarietyofapplicationsinall
marketsandcapacities.
RedHatEnterpriseLinuxdeliversthefullvalueofopensourcesoftware.How?Througha
commoncodebasefromlaptoptomainframe,asubscriptionmodelthatdeliversconstant
value,andadevelopmentmodelthatpreventsvendorlock-inandfostersinnovation.That’s
whyastudybyCIOInsightrankedRedHatthebestcompanyintheITindustryatdelivering
valuetocustomers—twoyearsinarow.#1atloweringITcosts,#1atmeetingreturnon
investmentexpectations,and#1atoverallvalue.
RedHatEnterpriseLinux5,releasedinearly2007,providesthelatestopensourcesoftware
technologies,whichofferimprovedperformance,securityandflexibilityandintroduces
integratedvirtualizationcapabilitiesforoperatingsystemsanddata.Thesubscription-based
packaginghasalsobeensimplifiedandstreamlined.Thispaperprovidesasummaryofafew
oftheseenhancements.
Red Hat Enterprise Linux 5 benefits summary•Enhancedfunctionalitythroughoutthe1200componentsthatmakeuptheproduct.
•Security:UnmatchedresistancetosecurityexploitsthroughtheinclusionofMulti-Level
Securityprofilesandimprovedcompilerandruntimebuffermanagementtechnologies.
•Desktopandproductivity:Dramaticallyimproveddesktopcapabilitiesandnew
applicationdevelopmenttoolsmakeworkinginaRedHatEnterpriseLinuxenvironment
betterthanever.
•Performanceandscalability:Extensiveenhancementstothekernel,networkandI/O
subsystemsensureoptimalperformanceusingthelatesthardwaresystems.
•Simplifiedpackaging:RedHatEnterpriseLinuxpackaginghasbeenstreamlinedto
eliminatetheformerAS/ES/WSvariants,makingiteasiertodeploy.
•Servers:
•RedHatEnterpriseLinuxAdvancedPlatform-providescomprehensiveserverand
storagevirtualizationcapabilitiesforserversofanysize.ExistingRedHat
EnterpriseLinuxAScustomerswillautomaticallymovetoRedHatEnterpriseLinux
AdvancedPlatformwhentheyrenewtheirsubscriptions.
•RedHatEnterpriseLinux-forserverswithupto2processorsockets,provides
traditionalEnterpriseLinuxfunctionalityandallthelatestfeatures,including
virtualization.ExistingRedHatEnterpriseLinuxEScustomerswillautomaticallymove
toRedHatEnterpriseLinuxwhentheyrenewtheirsubscriptions.
•Clients:
•RedHatEnterpriseLinuxDesktop-providesextensiveclientcapabilitiesinasingle
product,whichcanbeenhancedwithapairofoptions:WorkstationandMulti-OS.
RedHatEnterpriseLinuxWScustomerswillautomaticallymovetoRedHat
EnterpriseLinuxDesktopwiththeWorkstationoptionwhentheyrenewtheirsubscriptions.
� | www.redhat.com What’s New in Red Hat Enterprise Linux 5
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BasedontheLinux2.6.18kernel,RedHatEnterpriseLinux5representsthemoststable
andmaturecommercialLinuxavailable.ItisthefirstLinuxproducttodeliveramature,
commercial-strength,ready-to-deployvirtualizationcapability.RedHatEnterpriseLinux5
includestechnologiesthathavebeenextensivelytestedinFedoraProject,createdby
RedHatincollaborationwithmanycontributingopensourcepartnersandthecommunity.
VirtualizationRedHatEnterpriseLinux5providessophisticatedvirtualizationcapabilities.Thebenefitsof
virtualizationarebeingrapidlyrealizedbyITdepartmentseverywhere.Exampleusesinclude:
•Serverconsolidation-Withvirtualizationitispossibletoconsolidatetheloadofseveral
lightlyloadedserversontoone.
•Hardwareabstraction-Virtualizationmakesiteasytodeployanolderoperatingsystem
andapplicationonnewhardware.
•Resourcemanagementandhighavailability-Theabilitytomovevirtualizedoperating
systemsandtheirapplicationsbetweensystemsenablesworkloadstobehandledbythe
mostappropriatesystemandcontinuedoperationduringmaintenanceperiods.
AllRedHatEnterpriseLinuxserversoffervirtualizationcapabilities,usingtechnologybased
ontheopensourceXenproject.ARedHatEnterpriseLinuxhostcansupportpara-virtualized
guestsrunningRedHatEnterpriseLinux4.5and5.Itcanalsosupportfullyvirtualizedguests
runningRedHatEnterpriseLinux3andthird-partyoperatingsystems.Refertohttp://www.
redhat.comforthird-partyoperatingsystemsupportinformation.Ingeneral,para-
virtualizationofferssuperiorperformanceandrichermanagementcapabilitiesthanfull
virtualization,whilefullvirtualizationsupportsawiderrangeofguest
environments.Para-virtualizedguestscanbeconfiguredonanyserversystem
(32-bitx86withPAEsupportor64-bitx86)whilefullyvirtualizedguestsupport
requireshardwarefeaturesprovidedbyIntelVirtualizationTechnologyandAMD-
Vprocessors.Fullandpara-virtualizedguestscanbemixedonthesamephysical
system.
RedHatEnterpriseLinuxandRedHatEnterpriseLinuxAdvancedPlatformoffer
differinglevelsofvirtualizationcapabilities:
•Red Hat Enterprise Linux Advanced Platform:Providesacomplete,integrated
solutionbycouplingserverandstoragevirtualizationintoasingleproduct.For
mostproductionenvironments,theabilitytovirtualizetheserveroperating
systemdoesnotprovidethelevelofflexibilityoravailabilitydesired,sincethe
underlyingstorageinfrastructureisnotconsistentacrossvirtualorphysical
servers.Storagevirtualizationaddressesthisissuebyensuringthatstorage
logicalvolumesandfilesystemsareconsistentandcanbesharedbyallservers.
an Open sOuRce infRastRuctuRe fOR stabLe and matuRe cOmmeRciaL depLOyments
MACHINE 2
GUEST 5
GUEST 6
Hardware
Hardware
MACHINE 1
GUEST 1
GUEST 2
GUEST 3
Hardware
Hardware
GUEST 1
What’s New in Red Hat Enterprise Linux 5 www.redhat.com | 3
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Theresultisahighlyflexibleandmanagableenvironmentthatpermitscustomerstofully
realizethebenefitsofvirtualization.
RedHatEnterpriseLinuxAdvancedPlatformintegratestheRedHatstorageandclustering
capabilities:RedHatGlobalFileSystem(GFS)andRedHatClusterSuite.RedHatGFS
providesamulti-guestandmulti-hostshareablefilesystemandlogicalvolumemanager
thatallowapplicationdatatobesecurelyaccessedandsharedbyanyguestfromanysystem.
RedHatClusterSuiteprovidesfailoverateithertheapplicationorvirtualmachinelevel.
Additionally,RedHatEnterpriseLinuxAdvancedPlatformsupportsanunlimitednumberof
guestoperatingsystems.RedHatEnterpriseLinuxAdvancedPlatformprovidesthe
industry’smostcompleteandeffectivevirtualizedenvironment.
•Red Hat Enterprise Linux:Providesfullservervirtualizationcapbilities,supportingupto
fourguestoperatingsystems.
Bothproductsprovidenewvirtualizationmanagementcapabilities:
•libvirt/virsh-astandardizedlibrarythatallowsapplicationstomanagethevirtualized
environmentinastandard,consistentmanner.IdealforCIMproviders,libvirthasbindings
forC/C++andPython.Virsh,orvirtualshell,providesascriptablemanagementinterfacefor
libvirt.
•VirtManager-asophisticatedGUI-basedtoolformanagementofavirtualizedsystem.
Security enhancementsProvidingthehighestlevelsofsecurityisanoverridinggoaloftheRedHat
EnterpriseLinuxfamily.Buildingontheexcellentcapabilitiesofprevious
releases,version5includesanumberofenhancements.
Security-EnhancedLinux(SELinux)nowprovidessupportforMLS(MultiLevelSecurity)
policies.ThiswillenableRedHatEnterpriseLinux5toobtainUSGovernmentEAL4+/LSPP
(EvaluationAssuranceLevel/LabeledSecurityProtectionProfile)inadditiontotheexisting
EAL4+/CAPPcertification.ThismeansthatRedHatEnterpriseLinuxwillofferthehighest
levelofsecurityclearanceofanymainstreamoperatingsystem.
AllRedHatEnterpriseLinux5systemservicesareprovidedwithtargetedpolicies,andthese
areenabledbydefault,resultinginthehighestlevelofout-of-the-boxsecurityinthe
industry.Policycreationissimplifiedthroughtheintroductionofareferencepolicyand
supportforlocalpolicymodules,allowingISVsandcustomerstocreate
privatepolicies.
Significantease-of-useenhancementsareprovidedwiththeinclusionoftheSELinux
Troubleshooter,aGUI-basedanalyzerthatguidessystemadministratorsonappropriate
actionstotakeintheeventofasecurityalert.Thefigurebelowprovidesaviewofthisnew
managementcapability.
SELinuxistheonlyMandatoryAccessControl(MAC)implementationadoptedbythe
upstreamLinuxkerneland,assuch,enjoysextensivecollaborativesupportfrommany
securityorganizationsandITcompanies,includingUSGovernmentNationalSecurityAgency
(NSA),HP,IBM,Tresys,andTrustedComputerSolutions(TCS).Itisthedefactostandardfor
allcommunity-basedLinuxdistributions.
4 | www.redhat.com What’s New in Red Hat Enterprise Linux 5
CertifiCation
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Auditing
TheRedHatEnterpriseLinuxauditsubsystemletsyoutrackactivitiesand
modificationstotheentiresystem–includingfilesystemoperations,process
systemcalls,useractionssuchaspasswordchanges,accountadditions/deletions/
modification,useofauthenticationservices,andconfigurationchanges(suchastime
changes).ThisallowsRedHatEnterpriseLinux5tomeetUSGovernmentcertifications
suchasCAPP/LSPP&NISPOMandalsoassistorganizationstomeetregulatory
requirementssuchasSarbanesOxley&HIPPA.
Auditnowprovidespowerfulsearchingandreportingtools,andiscloselyintegratedwith
SELinux.Itistheonlyauditingsystemincorporatedintoupstreamcommunitykernel.
Auditalsoprovidesafeaturethatisuniqueintheindustry–areal-timeinterface.This
permitsapplicationstoanalyzeandreacttoeventsastheyoccur.Afutureupdatetothe
Auditcapabilitywillprovidemulti-systemlogaggregation.
AutoFSRedHatEnterpriseLinux5providesagreatlyenhancedAutoFScapabilityso
thatitnowinteroperatessmoothlyandsecurelyinmixedenvironments.
Newfeaturesinclude:
•DirectMapSupport–providingcompatibilitywithUNIXenvironments
What’s New in Red Hat Enterprise Linux 5 www.redhat.com | 5
SeCurity
uniX Compatibility
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• Lazy-mountandunmount–thisgreatlyreducesthenumberofsimultaneousmountson
clientsystems,therebyallowingefficientdeploymentinlargeNFSinfrastructures.
• MapscanbesharedwithSunSolaris,HP/UX,IBMAIX,andotherUNIXsystems.
• AuthenticatedbindswithLDAPserversusingKerberos,Digest-MD5,etc.
SambaRedHatEnterpriseLinuxincludesSambatoprovideinteroperabilitywith
MicrosoftWindowsfileandprint(CIFS)systems.Newfeaturesallowgreatlyimproved
integrationwithMicrosoftActiveDirectorywith,forexample,moreconsistentuserand
groupmapping,andbettersupportfornestedgroups.Extensivedevelopmentworkand
numerousenhancementshaveimprovedthequalityandstabilityoftheentiresubsystem.
FS-CacheFS-Cacheisanewfilesystemthatpermitsdatalocatedonaremotesystem,
suchasanNFSserver,tobecachedonalocalstoragedevice.Formemory-constrainedor
data-intensivesystems,thiseliminatestherequirementtorepeatedlyreadthesamedata
fromtheremotesystem.Theneteffectisincreasedclientperformanceandreduced
serverandnetworkload.
NFSRedHatEnterpriseLinux5providesthelatestNFSv4implementation,
offeringsignificantenhancementsinperformance,stabilityand,withSecureNFS,security
andserver-sidedelegation.
AllversionsofNFScannowusetheFS-Cachefacility.Filesystemsmountedwiththenew
‘fsc’mountoption,willcachedatapagesthatarereadfromtheserver.Notethatdata
pageswillstillexistafterthearebootorthefilesystemisunmounted/mounted,assuming
thedataontheserverhasnotchanged.
Global File System, Logical Volume Manager, and Distributed Lock ManagerInordertosimplifyseamlesssystemgrowthandvirtualizationadoption,the
baseRedHatEnterpriseLinux5productincludesstandalone(singlesystem/guest)
versionsofthreedistributedsystemtechnologies:
• LogicalVolumeManager(LVM)–forcreatingandmanagingpoolsofvirtualstorage
devices
• GlobalFileSystem(GFS)–ahighperformance,scalable,POSIX-compliantfilesystem.
GFSprovidessupportforfilesystemswithupto8EBtheoreticalcapacity(with25TB
certifiedcapacityatRedHatEnterpriseLinux5launch).
• DistributedLockManager(DLM)–asophisticatedapplicationsynchronizationinterface.
6 | www.redhat.com What’s New in Red Hat Enterprise Linux 5
WindoWS interoperability
performanCe
uniX interoperability
diStributed SyStemS SCalability & performanCe
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Standalonesystemsusingthesetechnologiescanbeeasilyupgradedtooperateinmulti-
systemandvirtualizedconfigurationsbyupgradingtoRedHatEnterpriseLinuxAdvanced
Platform,whichprovidescompatible,multi-systemandmulti-guest(cluster-wide)
versionsoftheLVM,GFSandDLM.Thisseamlessmigrationeliminatestheneedto
remapthestoragesubsystem,reformatdiskpartitions,orrewriteapplication
synchronizationroutineswhenmovingfromastandaloneservertoamulti-system
orvirtualizedconfiguration.
Application and virtual machine failoverRedHatEnterpriseLinuxAdvancedPlatformincludesclusterfailoversupport.
Thisallowsforapplicationsandvirtualmachinestobeautomaticallyrestartedor
dynamicallytransferredontoothermachinesinthecluster.Additionally,application
dependentresourcescanbedynamicallymonitoredtotriggerre-hostingofapplications
toalternatephysicalorvirtualmachinestoensurecontinuousoperation.
Enhanced storage capabilitiesAlargenumberofnewcapabilitiesareprovidedintheclustering,storage,filesystemand
interconnectspace.Theseinclude:
•TheExt3filesystemwillnowsupport16TBfilesystems.
•SystemsthatuseiSCSIandFibreChannelcanbeconfiguredduringRedHatEnterprise
Linuxinstallation.
•OpenAIS–TheApplicationInterfaceSpecificationisasoftwareAPIandsetofpolicies
whichareusedtodevelopapplicationsthatmaintainserviceduringfaults.TheAPI
consistsofAvailabilityManagementFramework(AMF)whichprovidesapplication
failover,ClusterMembership(CLM),Checkpointing(CKPT),Event(EVT),Messaging
(MSG),andDistributedLocks(DLOCK).AIScanmaskmanytypesoffaultsin
applications,middleware,operatingsystems,orevenhardwarebyprovidingasimple
frameworkforallowingdeveloperstocreateredundantapplications.Theseredundant
applicationscanbedistributedovermultiplenodessuchthatifanyonenodefaults,
anothernodecanrecover.
•Dm-cryptprovidesblock-levelstoragedeviceencryption.Dm-cryptcanbeusedto
providetransparentdataencryptionforanymountabledevice(including,forexample,
USBmemorysticks).Anencryptionkeyisspecifiedatmounttime;allwritestothe
devicearethenencryptedandallreadsdecrypted.Thisfeatureisespeciallyvaluable
forhigh-risksystems,suchaslaptops.
Red Hat NetworkTheRedHatNetworkclient-sidecomponent(Up2date)hasbeenreplacedwiththehighly
regarded,opensourceYumupdater,andusesPupasthegraphicaluserinterface.Yumis
abletoaccesspublicsoftwarerepositories,andaRedHatYumpluginenablesittoaccess
RedHatNetworkchannels.
What’s New in Red Hat Enterprise Linux 5 www.redhat.com | 7
availability
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RedHatEnterpriseLinuxDesktopincludesafullupdateofallthemajorcomponent
packages,andmanynewfeatures.MajorcomponentsincludeGNOME2.16,GTK2.10,Cups
1.2,andX.org7.1.Newfeaturesinclude:
GCC 4.1 CompilerRedHatEnterpriseLinux5isbuiltusingthelatestversionoftheindustry-standard
GNUCompilerCollectiontoolchain.Thedistributionisbuiltusingthefortify-sourcecompiler
flag,whichprovidesmorestringentrun-timebufferboundschecking,therebyaddingtooverall
systemsecurity.
AnumberofenhancementsareprovidedinGCC4.1andGlibc2.4forISVdevelopersand
thosedeployingapplications.Portabilityiseasedsignificantlyduetogreaterstandards
compliance.Thetoolchainalsoprovidescapabilitiesfor32-bitapplicationstorunon64-bit
systemsandyieldsbetteroveralloptimization,particularlyon64-bitarchitectures.RedHat
EnterpriseLinux5includescompatibilitylibrariesthatenableapplicationsthatwerepreviously
certifiedontheversions3and4torunwithoutrecompilation.Third-partyapplicationscanbe
certifiedonversion5usingtheexistingbinaryexecutablewiththecompatibilitylibrariesor
usingarecompiledbinarythatwillbenefitfromthenewcapabilitiesintherelease.
Systemtap and FryskAmajorgoalofRedHatEnterpriseLinux5istoprovideindustry-leadingapplication
developmenttools.Twoimportantnewfeaturesinclude:
•Systemtap–providesfunctionalitythatissimilartoSolarisDtrace–aninfrastructureto
simplifythegatheringofinformationabouttherunningkernel.Thisassistsdiagnosisofa
performanceorfunctionalproblem.Systemtapeliminatestheneedfordeveloperstogo
throughthetediousanddisruptiveinstrument,recompile,install,andrebootsequencethat
maybeotherwiserequiredtocollectdata.SystemtapprovidesbothGUIandcommandline
interfaces,andapowerfulscriptinglanguageforwritinginstrumentationforaliverunning
kernel.SystemtapistheresultofacollaborationbetweenRedHat,IBM,IntelandHitachi,and
isundergoingrapiddevelopment.ItisprovidedinRedHatEnterpriseLinux5asatechnology
preview.
•Frysk–providesanintelligent,distributed,always-onsystemmonitoringanddebuggingtool
thatallowsdevelopersandsystemadministratorstomonitorrunningprocessesandthreads
(includingcreationanddestructionevents),monitortheuseoflockingprimitives,expose
deadlocks,gatherdata,anddebuganygivenprocess.
Network ManagerNetworkManagerisanewconfiguratorthatautomaticallydetectsandconfigures
wirelessandwirednetworks.NetworkManagereliminatesmanualnetworkconfiguration.
8 | www.redhat.com What’s New in Red Hat Enterprise Linux 5
desktOp and pROductivity
StandardS ComplianCe
development toolS
eaSe of uSe
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Graphic subsystemTheOpenGL/GLXgraphicsubsystemhasbeen
significantlyenhanced,usingtheMetacitywidowmanagercoupledwiththeCompiz
compositingmanager–whichcantakeadvantageofOpenGLacceleration–poweredby
AIGLX.Forendusersthisresultsinanattractive,easy-to-useenvironmentwithfeatures
suchastranslucentwindows,fading,zooming,wobblywindows,andcube-style
workspaces.CommunityanddevicedriversupportforAIGLXisgrowingrapidly.
Additionally,thenewlymodularizedXsubsystemprovidesautoconfigurationofmost
graphicenvironments,significantstabilityimprovements,andsimplifiesmaintenance,
updates,andenhancements.
Hardware managementRedHatEnterpriseLinuxDesktopprovidesextensivesupportforlaptopcapabilitiessuch
assuspend/resumeandpowermanagement,andgreatlyenhanceddetectionofdevices
suchasprintersandcameras.
Smart Card LoginThenewSmartCardLogincapability,usingUSBtokensthatareenrolledina
PKIenvironmentsuchastheRedHatCertificateSystem,providesthecoretechnologyto
createsinglesign-onenvironmentsintegratedwithtechnologiessuchas
KerberosorTLS/SSL.
Thisallowsausertouseasmartcardtologintoaclientsystemandseamlessly
accessnetworkservices,suchaswebsitesandmailservers,usingeitherPKIor
Kerberosauthentication.
Additionally,FirefoxandThunderbirdhavebeenenhancedsothattheycannowuse
Kerberostoauthenticatetowebandmailservers.
What’s New in Red Hat Enterprise Linux 5 www.redhat.com | 9
SophiStiCated GraphiCS
SeCurity
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Stateless LinuxThetermStatelessLinuxreferstoanumberofcapabilitiesthat
willcombinetocreateanexcitingnewwaytoperformlarge-scalesystemdeploymentand
management.Manyofthefoundationalpieces–suchasNetworkManagerandX-windows
auto-configuration–arebeingprovidedforthefirsttimewiththereleaseofRedHat
EnterpriseLinux5,andyoucanexpecttoseeadditionalcapabilitiesandmanagement
toolsrolledoutovertime.
StatelessLinuxallowsyoutogaincontrolofthesituationwheremanysystems,serversor
clients,startoutasasingledeploymentbutdivergeovertimeasdifferentupgradesand
applicationsareinstalled.Itallowsyoutodefineasingleshareableimageforgroupsof
systems,largeorsmall.Thisimprovesoverallsystemsecurity,simplifiesthemanagement
oflargedeployments,andeasesthedeploymentofnewmachines.Essentially,itallows
hardwaretobecomeinterchangeable,becauseallsystemandapplicationstateis
managedoncentralizedservers.
StatelessLinuxwillbevaluedbycustomerslookingtodeployknowledge-workerdesktop
systemsandcorporatelaptops,aswellasvirtualcomputationorapplicationservers.
OptionsRedHatEnterpriseLinux5Desktopisavailablewithtwoexcitingnewoptions:
•Workstation–providessupportforlargerclientsystems,soitiswellsuitedforhigh-
performanceengineeringandtechnicalapplications
•MultiOS–allowsthedeploymentofvirtualizedguestoperatingsystems,sothata
desktopsystemcanrunbothRedHatEnterpriseLinuxDesktopand3rdpartyoperating
systemsatthesametime.
peRfORmance and scaLabiLityRedHatEnterpriseLinux5representstheresultofconcentrateddevelopmentspread
acrosstheentirecoreproduct,andLinuxkernelenhancementsaccruedfromversion
2.6.9to2.6.18.Thesemyriadincrementalenhancementscombinetoimprovethe
performanceandscalabilityofthesysteminmanyareas.Thefollowingexamplesprovide
aglimpseofthescopeoftheseenhancements.
•EnhancedI/Oschedulersaremodular,per-queue,andswitchableon-the-fly.Theypermit
I/Operformancetobeoptimizedonaper-devicebasisaccordingtotherequirementsof
theapplication.
•Anewpipeimplementationusescircularbuffers,whichdelivers30-90%
bandwidthimprovement.
10 | www.redhat.com What’s New in Red Hat Enterprise Linux 5
manaGeability
Page 11
•Anewkernelsplicefeaturepermitshigh-speedkernel-baseddatatransfers,eliminating
wastefulbuffercopies.
•SupportforIPv4/IPv6UDPfragmentationoffloadandoptimizedbuffermanagement
increasesnetworkperformancewithanynetworkadapter.Thefeaturealsotakes
advantageofadapteraccelerationfeatures,ifavailable,toachieveevenbetter
performance.
•Enhancementstothesystemschedulerprovideimprovedsupportforshared-cache
multi-coresystems.SupportforCPUsetsenablesmulti-process/threadapplicationsto
beoptimallyscheduledinlargeSMPandNUMAsystems.
•Supportforavastapplicationvirtualaddressspaceonx86-64systemsisavailableasa
resultofmemorymanagementenhancementsthatsupportfour-levelpagetables.
•ThescalabilityandperformanceoflargeSMPsystemsisimprovedthroughchanges
tothekernellockingsubsystem.Forexample,theconversionofcriticallocksto
semaphoresreducesSMPlockcontentioninmanyareasofthekernel,allowing
increasedkernelthreadconcurrencyandreducedresourcecontention.
Multipath I/OMultipathI/O(MPIO),whichisincludedaspartofRedHat
EnterpriseLinux,providesenhancedavailabilityandperformanceforstoragesystems.
WithMPIO,multiplephysicalSANconnectionsarecreatedbetweentheservernodeand
thestoragearray.Configurationstypicallyincluderedundantcablesandswitches,while
thestoragearraysusuallyhavetwocontrollers.Ifanyelement(cable,switch,controller)
fails,theMPIOsoftwarewillautomaticallyswitchtousingtheotherpath.
MPIOisconfiguredinoneoftwoprincipalways,dependentuponthestoragearray.Inan
active/passiveconfigurationonlyonepathisusedatanytimeforI/O.Whenafailureis
detected,theI/Oisre-routedoverthealternatepath.InActive/Activemodeallpaths
(therecanbemorethantwo)areusedfortheI/O.I/Oisspreadovertheconnectionsina
round-robinfashion,increasingthetotalI/Operformance.MPIOwasfirstintroducedasa
standardfeatureofRedHatEnterpriseLinux4;inversion5,MPIOisenhancedtoprovide
supportfortherootdeviceandcanalsobeconfiguredaspartofthesysteminstallation
process(usingAnaconda).
RedHatEnterpriseLinuxcontainsapproximately1200softwarecomponents,andthese
componentshavebeenundercontinuousdevelopmentbyRedHatanditspartnersforthe
two-yearperiodbetweenRedHatEnterpriseLinux4and5.Thisarticlehasdescribedonlya
fewofthemanynewfeatures.Fordetailedinformation,pleaserefertowww.redhat.comand
thesystemdocumentation.
What’s New in Red Hat Enterprise Linux 5 www.redhat.com | 11
performanCe & availability
©2007RedHat,Inc.AllRightsReserved.RedHat,RedHatEnterpriseLinux,theShadowmanlogoandJBossareregisteredtrademarksofRedHat,Inc.intheU.S.andothercountries.LinuxisaregisteredtrademarkofLinusTorvalds.Allothertrademarksarethepropertyoftheirrespectiveowners. RT#322012_2/07
LeaRn mORe abOut Red hat enteRpRise Linux 5
