What’s New in Performance in vSphere 5.0 – White Paper ......TECHNICAL WHITE PAPER / 3 What’s...

What’s New in Performance in VMware vSphere™ 5.0T E C H N I C A L W H I T E P A P E R

T E C H N I C A L W H I T E P A P E R / 2

What’s New in Performance in VMware vSphere 5.0

IntroductionVMware vSphere™ 5.0 (“vSphere”), the best VMware® solution for building cloud infrastructures, pushes further ahead in performance and scalability. vSphere 5.0 enables higher consolidation ratios with unequaled performance. It supports the build-out of private and hybrid clouds at even lower operational costs than before.

The following are some of the performance highlights:

VMware vCenter™ Server scalability •Fasterhigh-availability(HA)configurationtimes

•Fasterfailoverrates–60%morevirtualmachineswithinthesametime

•Lowermanagementoperationallatencies

•Highermanagementoperationsthroughput(Ops/min)

Compute•32-wayvCPUscalability

•1TBmemorysupport

Storage •vSphere®StorageI/OControl(StorageI/OControl)nowsupportsNFS–Setstoragequalityofservice

priorities per virtual machine for better access to storage resources for high-priority applications

Network•vSphere®NetworkI/OControl(NetworkI/OControl)–Givesahighergranularityofnetworkloadbalancing

vSphere vMotion®•vSpherevMotion®(vMotion)–Multi–networkadaptorenablementthatcontributestoanevenfastervMotion

•vSphereStoragevMotion®(StoragevMotion)–Fast,livestoragemigrationwithI/Omirroring

VMware vCenter Server and Scalability EnhancementsVirtual Machines per ClusterEven with the increased number of supported virtual machines per cluster, vSphere 5.0 delivers a higher throughput(Ops/min)ofmanagementoperations—upto120%,dependingontheintensityoftheoperations.Examples of management operations include virtual machine power-on, virtual machine power-off, virtual machinemigrate,virtualmachineregister,virtualmachineunregister,createfolder,andsoon.Operationlatencyimprovementsrangefrom25%to75%,dependingonthetypeofoperationandthebackgroundload.

HA (High Availability)SignificantadvanceshavebeenmadeinvSphere5.0toreduceconfigurationtimeandimprovefailoverperformance.A32-host,3,200–virtualmachine,HA-enabledclustercanbeconfigured9xfasterinvSphere5.0.Inthesameamountoftimeaswithpreviouseditions,vSphere5.0canfailover60%morevirtualmachines.Theminimalrecoverytime,fromfailuretothefirstvirtualmachinerestarts,hasbeenimprovedby44.4%.Theaveragevirtualmachinefailovertimehasimprovedby14%.

Inaddition,invSphere5.0,thedefaultCPUslotsize—thatis,spareCPUcapacityreservedforeachHA-protectedvirtualmachine—issmallerincomparisontoitsvalueinvSphere4.1,toenableahigherconsolidationratio.Asaresult,DistributedPowerManagement(DPM)mightbeabletoputmorehostsintostandbymodewhentheclusterutilizationislow,leadingtomorepowersavings.



VMware ESX VMware ESX VMware ESXi

VM VM

Resource Pool

Failed ServerOperating Server Operating Server

VMVM VMMVVMVVMMMMVVV VMVMVMMMMM VMVM

Figure 1. vSphere 5.0 High Availability

CPU Enhancements32-vCPU performance and scalabilityVMwarevSphere5.0cannowsupportupto32vCPUs.UsingalargenumberofvCPUsinavirtualmachinecanpotentiallyhelplarge–scale,mission–critical,Tier1applicationsachievehigherperformanceandthroughputand/orfasterruntimeforcertainapplications.

TheVMwarePerformanceEngineeringlabconductedavarietyofexperiments,includingcommercialTier1andHPC(high-performancecomputing)applications.Performancewasobservedclosetonative,92–97%,asvirtualizedapplicationsscaledto32vCPUs.

Intel SMT–related CPU scheduler enhancements IntelSMTarchitectureexposestwohardwarecontextsfromasinglecore.Thebenefitofutilizingtwohardwarecontextsrangesfrom10%to30%inimprovedapplicationperformance,dependingontheworkloads.InvSphere5.0,theVMware®ESXi™CPUscheduler’spolicyistunedforthistypeofarchitecturetobalancebetweenmaximumthroughputandfairnessbetweenvirtualmachines.InadditiontothenumberofperformanceoptimizationsmadearoundSMTCPUschedulinginvSphere4.1(runningtheVMwareESXihypervisorarchitecture),wehavefurther enhanced the SMT scheduler in VMware ESXi 5.0 to ensure high efficiency and performance for mission-critical applications.

Virtual NUMA (vNUMA) VirtualNUMA(vNUMA)exposeshostNUMAtopologytotheguestoperatingsystem,enablingNUMA-awareguestoperatingsystemsandapplicationstomakethemostefficientuseoftheunderlyinghardware’sNUMAarchitecture.

VirtualNUMA,whichrequiresvirtualhardwareversion8,canprovidesignificantperformancebenefitsforvirtualizedoperatingsystemsandapplicationsthatfeatureNUMAoptimization.



Storage EnhancementsNFS support for Storage I/O Control vSphere5.0StorageI/OControlnowsupportsNFSandnetwork-attachedstorage(NAS)–basedsharesonshareddatastores.ItnowprovidesthefollowingbenefitsforNFS:

•Dynamicallyregulatesmultiplevirtualmachines’accesstosharedI/Oresources,basedondisksharesassignedto the virtual machines.

•Helpsisolateperformanceoflatency-sensitiveapplicationsthatemploysmaller(<8KB)randomI/Orequests.Thishasbeenshowntoincreaseperformancebyasmuchas20%.

•Redistributesunutilizedresourcestothosevirtualmachinesthatneedtheminproportiontothevirtualmachines’diskshares.Thisresultsinafairallocationofstorageresourceswithoutanylossinutilization.

•LimitsperformancefluctuationsofacriticalworkloadtoasmallrangeduringperiodsofI/Ocongestion. Thisresultsinuptoan11%performancebenefitcomparedtothatinanunmanagedscenariowithout StorageI/OControl.

StorageI/OControlprovidesadynamiccontrolmechanismformanagingvirtualmachines’accesstoI/Oresources,FibreChannel(FC),iSCSIorNFS,inacluster.ItdeliversthesameperformancebenefitstoNFSdatastoresasitdoestoalreadysupportedFCoriSCSIdatastores.Testshaveshownthatwiththerightbalanceofworkloads,StorageI/OControlmightimproveperformanceofcriticalapplicationsbyasmuchas10%, withalatencyimprovementperI/Ooperationofasmuchas33%.

VMVM VM VM VM

VIP

VM

VIP

With StorageI/O Control

Without StorageI/O Control

OnlineStore

MicrosoftExchange

OnlineStore

DataMining

PrintServer

DataMining

PrintServer

MicrosoftExchange

VM VM VMVMVM VM

During high I/O from non-critical application

Figure 2. vSphere 5.0 Storage I/O Control



Memory Management Enhancements1TB vMem support InvSphere5.0,virtualmachinescannowsupportvMemupto1TB.Withthenew1TBvMemsupport,Tier1applicationsconsuminglargeamountsofmemory(>255GB),suchasin-memorydatabases,cannowbevirtualized.Experimentalmeasurementswithmemoryintensiveworkloadsforvirtualmachineswithupto 1TBvMemdemonstratesimilarperformancewhencomparedtoidenticalphysicalconfigurations.

SSD Swap Cache vSphere5.0canbeconfiguredtoenableVMwareESXihostswappingtoasolid-statedisk(SSD).Inthelowhostmemory–availablestates(highmemoryusage),whereguestballooning,transparentpagesharing(TPS)andmemory compression have not been sufficient to reclaim the needed host memory, hypervisor swapping is used as the last resort to reclaim memory from the virtual machines. vSphere employs three methods to address limitations of hypervisor swapping to improve hypervisor swapping performance:

•Randomlyselectingthevirtualmachinephysicalpagestobeswappedout.ThishelpsmitigatetheimpactofVMwareESXipathologicallyinteractingwiththeguestoperatingsystem’smemorymanagementheuristics.This has been enabled from early releases of VMware ESX®.

•MemorycompressionofthevirtualmachinepagesthataretargetedbyVMwareESXitobeswappedout.Thisfeature,introducedinvSphere4.1,reducesthenumberofmemorypagesthatmustbeswappedouttothedisk,whilereclaiminghostmemoryeffectivelyatthesametimeandtherebybenefitingapplicationperformance.

•vSphere5.0nowenablesuserstochoosetoconfigureaswapcacheontheSSD.VMwareESXi5.0willthenusethis swap cache to store the swapped-out pages instead of sending them to the regular and slower hypervisor swapfileonthedisk.Uponthenextaccesstoapageintheswapcache,thepagewillberetrievedquicklyfromthecacheandthenremovedfromtheswapcachetofreeupspace.BecauseSSDreadlatenciesareanorderofmagnitudefasterthantypicaldiskaccesslatencies,thissignificantlyreducestheswap-inlatenciesandgreatlyimproves the application performance in high memory over commitment scenarios.

SSD Swap Cache

Flash

Page Table

01101001

Main Memory

Figure 3. SSD Swap Cache



Network EnhancementsNetwork I/O ControlNetworkI/OControl(NIOC)enablestheallocationofnetworkbandwidthtoresourcepools.InvSphere5.0,userscancreatenewresourcepoolstoassociatewithportgroupsandspecify802.1ptags,whereasinvSphere4.1,onlypredefinedresourcepoolscouldbeusedforbandwidthallocation.Sodifferentvirtualmachinescannowbeindifferentresourcepoolsandbegivenahigherorlowershareofbandwidththantheothers.ThepredefinedresourcegroupsincludevMotion,NFS,iSCSI,vSphere®FaultTolerance(FaultTolerance),virtualmachine,andmanagement.

splitRxModevSphere5.0introducesanewwayofdoingnetworkpacketreceiveprocessingintheVMkernel.InpreviousreleasesofvSphere,allreceivepacketprocessingforanetworkqueuewasdoneinasinglecontext,whichmightbe shared among various virtual machines. In cases where there is a higher density of virtual machines per networkqueue,itispossibleforthecontexttobecomeresourceconstrained.Multicastisonesuchworkloadwheremultiplereceivervirtualmachinesshareonenetworkqueue.vSphere5.0includesanewmechanismtosplitthecostofreceivepacketprocessingtomultiplecontexts.SplitRxModecanspecifyforeachvirtualmachinewhetherreceivepacketprocessingshouldbeinthenetworkqueuecontextoraseparatecontext.

WecalledthismodesplitRxMode,anditcanbeenabledonaper-vNICbasisbyeditingtheVMXfileofthevirtualmachinewithethernetX.emuRxMode=“1”fortheEthernetdevice.

NOTE: This configuration is available only with vmxnet3. Once the option is enabled, the packet processing for the virtual machine is handled by a separate context. This improves the multicast performance significantly. However, there is an overhead associated with splitting the cost among various PCPUs. This cost can be attributed to higher CPU utilization per packet processed, so VMware recommends enabling this option for only those workloads, such as multicast, that are known to benefit from this feature.

VMware performance labs conducted a performance study for multiple receivers with the sender transmitting multicastpacketsat16,000packetspersecond.Aseachadditionalreceiverwasadded,therewasanincrease inpacketshandledbythenetworkingcontext.Aftertheloadofthecontextreacheditsmaximum,thereweresignificantpacketlosses.ByenablingsplitRxModeonthesevirtualmachines,theloadonthecontextwasdecreasedandtherebyincreasingthenumberofmulticastreceivershandledwithoutsignificantdrops.Figure4showsthatthereisnonoticeabledifferenceinlossrateforthesetupuntilthereare24virtualmachinespoweredon.Aftertherearemorethan24virtualmachinespoweredon,thereisanalmost10–25%packetloss.EnablingsplitRxModeforthevirtualmachinesreducesthelossratetolessthan0.01%.

Multicast Performance

Default

splitRxMode

Perc

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acke

t Los

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15

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01 2 4 8 12 16 24 28 32

Number of Receivers

Figure 4. Multicast Performance



vSphere DirectPath I/O vSphere®DirectPathI/O(DirectPathI/O)enablesguestoperatingsystemstodirectlyaccessnetworkdevices.DirectPathI/OforvSphere5.0hasbeenenhancedtoallowthevMotionofavirtualmachinecontainingDirectPathI/OnetworkadaptorsontheCiscoUnifiedComputingSystem(UCS)platform.Onsuchplatforms,with proper setup and ports available for passthrough, vSphere 5.0 can transition the device from one that is paravirtualizedtoonethatisdirectlyaccessed,andtheotherwayaround.Whilebothmodescansustainhighthroughput(beyond10Gbps),directaccesscanadditionallysaveCPUcyclesinworkloadswithhighpacketrates(forexample,approximatelygreaterthan50kps).

BecauseDirectPathI/OdoesnotsupportsomevSpherefeatures—memoryovercommitmentandNIOC—VMwarerecommendsusingDirectPathI/Oonlyforworkloadswithveryhighpacketrates,wheresavingCPUcycles can be critical to achieving the desired performance.

Host Power Management EnhancementsVMware®HostPowerManagement(VMwareHPM)invSphere5.0providespowersavingsworkingatthehostlevel.WithvSphere5.0,thedefaultpowermanagementpolicyis“balanced.”Thebalancedpolicyusesanalgorithmthatexploitsaprocessor’sP-states.WorkloadsoperatingunderlowCPUloadscanexpecttoseesomepowersavings(dependingentirelyontheworkloadCPUusagecharacteristics)withminimalperformanceloss(dependentonapplicationCPUusagecharacteristics).VMwarestronglyadvisesperformance-sensitiveuserstoconductcontrolledexperimentstoobservethepowersavings/performanceoftheirapplicationwithvSphere 5.0. If the performance loss is unacceptable, switch VMware ESX to the “high performance” mode. Most oftheworkloadsoperatingunderlowloadscanseeupto5%inpowersavingswhenusingbalancedmode.



VMware vMotionMulti–network adaptor enablement for vMotionThenewperformanceenhancementsinvSphere5.0enablevMotiontoeffectivelysaturatea10GbEnetworkadaptorbandwidthduringthemigration,significantlyreducingvMotiontransfertimes.Inaddition,VMwareESX5.0addsamulti-networkadaptorfeaturethatenablesuserstoemploymultiplenetworkadaptorsforvMotion.TheVMkernelwilltransparentlyload-balancethevMotiontrafficoverallthevMotion-enabledvmknicsinanefforttosaturatealloftheconnections.Infact,evenwhenthereisasinglevMotion,VMkernelusesalltheavailablenetworkadaptorstospreadthevMotiontraffic.

Figure5summarizesthevMotionperformanceenhancementsinvSphere5.0overvSphere4.1.Thetestenvironmentmodeledbothasingle-instanceSQLservervirtualmachine(virtualmachineconfiguredwithfourvCPUsand16GBmemoryandrunningOLTPworkload)andmultiple-instanceSQLservervirtualmachine(eachvirtualmachineconfiguredwithfourvCPUsand16GBmemoryandrunningOLTPworkload)deploymentscenariosforthefollowingconfigurations:

1. vSphere 4.1: Source/Destination hosts configured with a single 10GbE port for vMotion

2. vSphere 5.0: Source/Destination hosts configured with a single 10GbE port for vMotion

3. vSphere 5.0: Source/Destination hosts configured with two 10GbE ports for vMotion

vSphere 4.1

vSphere 5

vSphere 5 (2 NICs)

1 Virtual Machine

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Figure 5. vMotion Performance in vSphere 4.1 and vSphere 5.0

ThefigureclearlyshowstheenhancementsmadeinvSphere5.0toreducethetotalelapsedtimeinboth single–virtualmachineandmultiple-instanceSQLservervirtualmachinedeploymentscenarios.TheaveragepercentagedropinvMotiontransfertimewasalittleover30%invSphere5.0whenusingasingle10GbEnetworkadaptor.Whenusingtwo10GbEnetworkadaptorsforvMotion(enabledbythenewmulti–networkadaptorfeatureinvSphere5.0),thetotalmigrationtimereduceddramatically:afactorof2.3ximprovementoverthevSphere4.1result.Thefigurealsoillustratesthefactthatthemulti–networkadaptorfeaturetransparentlyloadbalancesthevMotiontrafficontomultiplenetworkadaptors,eveninthecasewhereasinglevirtual machine is subjected to vMotion. This feature can be especially handy when a virtual machine is configuredwithalargeamountofmemory.



Metro vMotionvSphere 5.0 introduces a new latency-aware “Metro vMotion” feature that provides better performance over longlatencynetworksandalsoincreasestheround-triplatencylimitforvMotionnetworksfrom5millisecondsto10milliseconds.Previously,vMotionwassupportedonlyonnetworkswithround-triplatenciesofupto 5 milliseconds.

VMware Storage vMotion (Live Migration) EnhancementsvSphere5.0nowsupportslivemigrationforstoragewiththeuseofI/Omirroring.Inpreviousreleases,livemigration moved memory and device state only for a virtual machine, limiting migration to hosts with identical sharedstorage.Livestoragemigrationovercomesthislimitationbyenablingthemovementofvirtualdisksspanningvolumesanddistance.Thisenablesgreatervirtualmachinemobility,zerodowntimemaintenanceandupgrades of storage elements, and automatic storage load balancing.

VMwarehasbeenabletogreatlyreducethetimeittakesforthestoragetomigrate,startingwiththeuseofsnapshotsinVirtualInfrastructure3.5,movingtousingdirtyblocktrackinginvSphere4.0,andnowtousingI/Omirroring in vSphere 5.0.

Livestoragemigrationhasthefollowingadvantages.

•Zerodowntimemaintenance– Enables customers to move virtual machines on and off storage volumes, upgradestoragearrays,performfilesystemupgrades,andservicehardwarewithoutpoweringdown virtual machines.

•Manualandautomaticstorageloadbalancing–Customerscancontinuetomanuallyload-balancetheirvSphereclusterstoimprovestorageperformance,ortheycantakeadvantageofautomaticstorageloadbalancing(vSphere®StorageDRS),whichisnowavailableinvSphere5.0.

•Livestoragemigrationincreasesvirtualmachinemobility– Virtual machines are no longer pinned to the storagearraytheyareinstantiatedon.Livemigrationworksbycopyingthememoryanddevicestateofavirtual machine from one host to another with negligible virtual machine downtime.

VMware ESXi & ESX

VM VM VMVM

Storage vMotion

Figure 6. vSphere 5.0 Storage vMotion

T E C H N I C A L W H I T E P A P E R / 1 0


Tier 1 Application PerformanceMicrosoft Exchange Server 2010MicrosoftExchangeServer2010significantlybenefitsfromthesuperiorperformanceandscalabilityprovidedbyvSphere5.0.MicrosoftExchangeLoadGenerator2010benchmarkresultsindicatethatvSphere5.0improvesMicrosoft Exchange transaction response times and vMotion and Storage vMotion migration times when compared with the previous vSphere release.

ThefollowingareexamplesofperformanceandscalabilitygainsobservedincomparisontovSphere4.1:

•6%reductioninSendMail95thpercentiletransactionlatencieswithafour-vCPUExchangeMailBoxservervirtual machine

•13%reductioninSendMail95thpercentiletransactionlatencieswithaneight-vCPUExchangeMailBoxservervirtual machine

•33%reductioninvMotionmigrationtimeforafour-vCPUExchangeMailBoxservervirtualmachine

•11%reductioninStoragevMotionmigrationtimefora350GBExchangedatabaseVMDK

ZimbraMailServerPerformanceThefull-featured,robustandopen-sourceZimbraCollaborationSuite(ZCS)includesemail,calendaring,andcollaboration software. Zimbra is an important part of the VMware cloud computing portfolio, as software as a service(SaaS)andasaprepackagedvirtualapplianceforSMBs.

ForvSphere5.0,virtualizedZCSperformswithin95%ofnativeperformancevirtualmachine,scalinguptoeightvCPUs.Uptoeight4-vCPUZCSvirtualmachinessupporting32,000mailuserswerescaledoutonasinglehostwithjusta10%increaseinSendmaillatenciescomparedtoasinglevirtualmachine.

Inrecent4-vCPUexperiments,ZCShaslessthanhalftheCPUconsumptionofExchange2010withthesamenumberofusers,andmailuserprovisiontimeforZCSwas10xfaster.

Zimbra MTA+LDAP/Exchange 2010 CAS+HUB

Zimbra Database/Exchange 2010 Indexing

Mailbox

% C

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Figure 7. Zimbra CPU Efficiency over Exchange 2010


VMware, Inc. 3401 Hillview Avenue Palo Alto CA 94304 USA Tel 877-486-9273 Fax 650-427-5001 www.vmware.comCopyright © 2011 VMware, Inc. All rights reserved. This product is protected by U.S. and international copyright and intellectual property laws. VMware products are covered by one or more patents listed at http://www.vmware.com/go/patents. VMware is a registered trademark or trademark of VMware, Inc. in the United States and/or other jurisdictions. All other marks and names mentioned herein may be trademarks of their respective companies. Item No: VMW-WP-PERFORMANCE-USLET-101

SummaryVMware innovations continue to ensure that VMware vSphere 5.0 pushes the envelope of performance and scalability.ThenumerousperformanceenhancementsinvSphere5.0enableorganizationstogetevenmoreoutoftheirvirtualinfrastructureandfurtherreinforcetheroleofVMwareasindustryleaderinvirtualization.

vSphere 5.0 represents advances in performance, to ensure that even the most resource-intensive applications, such as large databases and Microsoft Exchange email systems, can run on private, hybrid and public clouds powered by vSphere.

References (www.vmware.com)Understanding Memory Resource Management in VMware vSphere 5

Managing Performance Variance of Applications Using Storage I/O Control in VMware vSphere 5

Performance Best Practices Guide for VMware vSphere 5

Zimbra Mail Performance on VMware vSphere 5

Host Power Management in VMware vSphere 5

www.vmware.com

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