VMware vSphere Performance WP En

7/31/2019 VMware vSphere Performance WP En

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Whats New in VMwarevSphere

4: Performance

EnhancementsW H I T E P A P E R


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Ws New in VMwe vSpee 4:Pefomnce Enncemens

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

Table of Contents

Scalability Enhancements 3

CPU Enhancements 4

Memory Enhancements 4

Storage Enhancements 5

Networking Enhancements 7

Resource Management Enhancements 9

Perormance Management Enhancements 10

Application Perormance 10

Oracle 10

SQL Server 11

SAP 12

Exchange 12

Summary 13

Reerences 13


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VMware vSphere 4, the industrys rst cloud operating system, includes several unique new eatures that allow

IT organizations to leverage the benets o cloud computing, with maximum eciency, uncompromised control,

and fexibility o choice. The new VMware vSphere 4 provides signicant perormance enhancements that

make it easier or organizations to virtualize their most demanding and intense workloads. These perormance

enhancements provide VMware vSphere 4 with better:

Efficiency:

Optimizations resulting in reduced virtualization overheads and highest consolidation ratios.

Control:

Enhancements leading to improved ongoing perormance monitoring and management, as well as

dynamic resource sizing or better scalability.

Choice:

Improvements that provide several options o guest OS, virtualization technologies, comprehensive HCL,

integrations with 3rd-party management tools to choose rom.

This document outlines the key perormance enhancements o VMware vSphere 4, organized into ollowing

categories:

ScalabilityEnhancements

CPU,Memory,Storage,Networking

ResourceManagement

PerformanceManagement

Finally, the white paper showcases the perormance improvements in various tier-1 enterprise applications as a

result o these benets.

ScalabilityEnhancements

A summary o the key new scalability improvements o vSphere 4 as compared to VMwares previous

datacenter product, VMware Inrastructure 3 (VI3), is shown in the ollowing table:

FEaturE VI3 VSPhErE 4

VirtualMachineCPUCount 4vCPUs 8vCPUs

Virtual Machine Memory Maximum 64 GB 255 GB

HostCPUCoreMaximum 32 cores 64 cores

Host Memory Maximum 256 GB 1 TB

Powered-onVMsperESX/ESXiMaximum 128 320

For details see Systems Compatibility Guide and Guest Operating System Installation Guide.

Additional changes that enhance the scalability o vSphere include:

64LogicalCPUsand512VirtualCPUsPerHost ESX/ESXi4.0providesheadroomformorevirtual

machines per host and the ability to achieve even higher consolidation ratios on larger machines.

64-bitVMkernel TheVMkernel,acorecomponentoftheESX/ESXi4.0hypervisor,isnow64-bit.This

provides greater host physical memory capacity and more seamless hardware support than earlier releases.

64-bitServiceConsole TheLinux-basedServiceConsoleforESX4.0hasbeenupgradedtoa64-bit

version derived rom a recent release o a leading Enterprise Linux vendor.


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NewVirtualHardwareESX/ESXi4.0introducesanewgenerationofvirtualhardware(virtualhardware

version 7) which adds signicant new eatures including:

Serial Attached SCSI (SAS) virtual device for Microsoft Cluster Service Providessupportforrunning

Windows Server 2008 in a Microsot Cluster Service conguration.

IDE virtual device Ideal or supporting older operating systems that lack SCSI drivers.

VMXNET Generation 3SeetheNetworkingsection.

Virtual Machine Hot Plug SupportProvidessupportforaddingandremovingvirtualdevices,adding

virtualCPUs,andaddingmemorytoavirtualmachinewithouthavingtopowerothevirtualmachine.

Hardwareversion7isthedefaul tfornewESX/ESXi4.0virtualmachines.ESX/ESXi4.0willcontinuetorun

virtualmachinescreatedonhostsrunningESXServerversions2.xand3.x.Virtualmachinesthatusevirtual

hardwareversion7featuresarenotcompatiblewithESX/ESXireleasespriortoversion4.0.

VMDirectPathforVirtualMachines VMDirectPathI/OdeviceaccessenhancesCPUeciencyinhandling

workloadsthatrequireconstantandfrequentaccesstoI/Odevicesbyallowingvirtualmachinesto

directly access the underlying hardware devices. Other virtualization eatures, such as VMotion, hardware

independenceandsharingofphysicalI/Odeviceswillnotbeavailabletothevirtualmachinesusingthis

feature.VMDirectPathI/OfornetworkingI/OdevicesisfullysupportedwiththeIntel8259810Gigabit

Ethernet Controller and Broadcom 57710 and 57711 10 Gigabit Ethernet Controller. It is experimentally

supportedforstorageI/OdeviceswiththeQLogicQLA25xx8GbFibreChannel,theEmulexLPe120008Gb

FibreChannel,andtheLSI3442e-Rand3801e(1068chipbased)3GbSASadapters.

IncreasedNFSDatastoreSupportESXnowsupportsupto64NFSsharesasdatastoresinacluster.

CPUEnhancements

Resource Management and Processor Scheduling

TheESX4.0schedulerincludesseveralnewfeaturesandenhancementsthathelpimprovethethroughputofall

workloads,withnotablegainsinI/Ointensiveworkloads.Thisincludes:

Relaxedco-schedulingofvCPUs,introducedinearlierversionsofESX,hasbeenfurtherne-tunedespeciallyforSMPVMs.

ESX4.0schedulerutilizesnewner-grainedlockingthatreducesschedulingoverheadsincaseswhere

requent scheduling decisions are needed.

Thenewschedulerisawareofprocessorcachetopologyandtakesintoaccounttheprocessorcache

architecturetooptimizeCPUusage.

ForI/Ointensiveworkloads,interruptdeliveryandtheassociatedprocessingcostsmakeupalargecomponent

o the virtualization overhead. The above scheduler enhancements greatly improve the eciency o interrupt

delivery and associated processing.

MemoryEnhancements

Hardware-assisted Memory Virtualization

Memorymanagementinvirtualmachinesdiersfromphysicalmachinesinonekeyaspect:virtualmemory

address translation. Guest virtual memory addresses must be translated rst to guest physical addresses using

the guest OSs page tables beore nally being translated to machine physical memory addresses. The latter

stepisperformedbyESXbymeansofasetofshadowpagetablesforeachvirtualmachine.Creatingand

maintainingtheshadowpagetablesaddsbothCPUandmemoryoverhead.


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Hardware support is available in current processors to alleviate this situation. Hardware-assisted memory

managementcapabilitiesfromIntelandAMDarecalledEPTandRVI,respectively.Thissupportconsistsofa

second level o page tables implemented in hardware. These page tables contain guest physical to machine

memoryaddresstranslations.ESX4.0introducessupportfortheIntelXeonprocessorsthatsupportEPT.

SupportforAMDRVIhasexistedsinceESX3.5.

Apache Compile

60%

50%

40%

30%

0%

10%

Eciency Improvement

20%

SQL Server Citrix XenApp

Efficiency Improvement

Figure1Eciencyimprovementsusinghardware-assistedmemoryvirtualization

Figure 1 illustrates eciency improvements seen or a ew example workloads when using hardware-assisted

memory virtualization.

While this hardware support obviates the need or maintaining shadow page tables (and the associated

performanceoverhead)itintroducessomecostsofitsown.Translationlook-asidebuer(TLB)misscosts,in

theformofincreasedlatency,arehigherwithtwo-levelpagetablesthanwiththeone-leveltable.Usinglarge

memorypages,afeaturethathasbeenavailablesinceESX3.5,thenumberofTLBmissescanbereduced.

Since TLB miss latency is higher with this orm o hardware virtualization assist but large pages reduce the

number o TLB misses, the combination o hardware assist and large page support that exists in vSphere yields

optimal perormance.

StorageEnhancements

A variety o architectural improvements have been made to the storage subsystem o vSphere 4. The

combinationofthenewparavirtualizedSCSIdriver,andadditionalESXkernel-levelstoragestackoptimizations

dramaticallyimprovesstorageI/Operformancewiththeseimprovements,allbutaverysmallsegmentofthe

mostI/OintensiveapplicationsbecomeattractivetargetsforVMwarevirtualization.

VMware Paravirtualized SCSI (PVSCSI)

Emulated versions o hardware storage adapters rom BusLogic and LSILogic were the only choices available

inearlierESXreleases.Theadvantageofthisfullvirtualizationisthatmostoperatingsystemsshipdriversfor


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these devices. However, this precludes the use o perormance optimizations that are possible in virtualized

environments.Tothisend,ESX4.0shipswithanewvirtualstorageadapterParavirtualizedSCSI(PVSCSI).

PVSCSIadaptersarehigh-performancestorageadaptersthatoergreaterthroughputandlowerCPUutilization

forvirtualmachines.TheyarebestsuitedforenvironmentsinwhichguestapplicationsareveryI/Ointensive.

PVSCSIadapterextendstothestoragestackperformancegainsassociatedwithotherparavirtualdevicessuch

asthenetworkadapterVMXNETavailableinearlierversionsofESX.Aswithotherdeviceemulations,PVSCSI

emulation improves eciency by:

Reducingthecostofvirtualinterrupts

BatchingtheprocessingofI/Orequests

BatchingI/Ocompletioninterrupts

A urther optimization, which is specic to virtual environments, reduces the number o context switches

betweentheguestandVirtualMachineMonitor.EciencygainsfromPVSCSIcanresultinadditional2xCPU

savingsforFibreChannel(FC),upto30percentCPUsavingsforiSCSI.

S/W iSCSI

1.2

1

0.8

0.6

0

0.2

LSI Logic

pvscsi

0.4

Protocol

Fibre Channel

PVSCSI Efficiency of 4K Block

I/0s

Figure2EciencygainswithPVSCSIadapter

VMware recommends that you create a primary adapter or use with a disk that will host the system sotware

(bootdisk)andaseparatePVSCSIadapterforthediskthatwillstoreuserdata,suchasadatabaseormailbox.The primary adapter will be the deault or the guest operating system on the virtual machine. For example, or

virtual machines with Microsot Windows 2008 guest operating systems, LSI Logic is the deault primary adapter.

iSCSI Support Improvements

vSphere 4 includes signicant updates to the iSCSI stack or both sotware iSCSI (that is, in which the iSCSI

initiatorrunsattheESXlayer)andhardwareiSCSI(thatis,inwhichESXleveragesahardware-optimized

iSCSIHBA).Thesechangesoerdramaticimprovementofbothperformanceaswellasfunctionalityofboth


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softwareandhardwareiSCSIanddeliveringsignicantreductionofCPUoverheadforsoftwareiSCSI.Eciency

gainsforiSCSIstackcanresultin7-26percentCPUsavingsforread,18-52percentforwrite.

HW iSCSI

60

50

40

30

0

10

Read

Write

20

SW iSCSI

iSCSI % CPU Efficiency Gains, ESX 4 vs. ESX 3.5

Figure3iSCSI%CPUEciencyGainsESXvsESX

Software iSCSI and NFS Support with Jumbo Frames

vSphere4addssupportforJumboFrameswithbothNFSandiSCSIstorageprotocolson1Gbaswellas10GbNICs.The10GbsupportforiSCSIallowsfor10xI/Othroughputmoredetailsinnetworkingsectionbelow.

Improved I/O Concurrency

AsynchronousI/OexecutionhasalwaysbeenafeatureofESX.However,ESX4.0hasimprovedtheconcurrency

ofthestoragestackwithanI/OmodethatallowsvCPUsintheguesttoexecuteothertasksafterinitiating

anI/OrequestwhiletheVMkernelhandlestheactualphysicalI/O.InVMwaresFebruary2009announcement

onOracleDBOLTPperformancethegainsattributedtothisimprovedconcurrencymodelweremeasuredat

5 percent.

NetworkingEnhancements

Signicant changes have been made to the vSphere 4 network subsystem, delivering dramatic perormance

improvements.

VMXNET Generation 3vSphere4includes,VMXNET3,thethirdgenerationofparavirtualizedNICadapterfromVMware.New

VMXNET3featuresoverpreviousversionofEnhancedVMXNETinclude:

MSI/MSI-Xsupport(subjecttoguestoperatingsystemkernelsupport)

ReceiveSideScaling(supported inWindows2008whenexplicitlyenabledthroughthedevicesAdvanced

conguration tab)


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IPv6checksumandTCPSegmentationOoading(TSO)

overIPv6

VLANo-loading

LargeTX/RXringsizes(conguredfromwithinthevirtualmachine)

Network Stack Performance and Scalability

vSphere 4 includes optimizations to the network stack that can saturate 10Gbps links or both transmit and

receivesidenetworkI/O.TheimprovementsintheVMkernelTCP/IPstackalsoimprovebothiSCSIthroughput

as well as maximum network throughput or VMotion.

vSphere4utilizestransmitqueuestoprovide3Xthroughputimprovementsintransmitperformanceforsmall

packet sizes.

1 VM 4 VMs 8 VMs

100%

80%

60%

0%

20%

Gains Over ESX 3.5

40%

16 VMs

Network Transmit Throughput Improvement

Figure 4NetworkTransmitThroughputImprovementorvSphere

vSphere4supportsLargeReceiveOoad(LRO),afeaturethatcoalescesTCPpacketsfromthesame

connectiontoreduceCPUutilization.UsingLROwithESXprovides40percentimprovementinboth

throughputandCPUcosts.


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ResourceManagementEnhancements

VMotion

PerformanceenhancementsinvSphere4reducetimetoVMotionaVMbyupto75percent.

Storage VMotion Performance

Storage VMotion is now ully supported (experimental beore) and has much improved switchover time. For

veryI/OintensiveVMs,thisimprovementcanbe100x.StorageVMotionleveragesanewandmoreecient

blockcopymechanismcalledChangedBlockTracking,minimizingCPUandmemoryresourceconsumptionon

theESXhostuptotwotimes.

Storage VMotion Time

ESX 3.5 ESX 4

1200

1000

800

600

0

200

400

20 VM Provisioning Time

ESX 3.5

1200

1000

800

600

0

200

400

ESX 4

Figure 5DecreasedStorageVMotionTime Figure 6ImprovedVMFSPerormance

During SPECjbb (ACTIVE)

Seconds(lowerisbetter)

600.00

500.00

400.00

300.00

0.00

100.00

4GB ESX 3.5

4GB ESX 4

200.00

After SPECjbb (IDLE)

Elapsed VMotion Time

Figure 7PerormanceEnhancementsLeadtoaReducedTimetoVMotion


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

25

ESX 3.5

512 VM Boot Storm (FCP)

ESX 4

20

15

0

5

10

512 VM Boot Time

(Fibre Channel)

Figure 8TimetoBoot2VDIVMS

VM Provisioning

VMFSperformanceimprovementsoermoreecientVMcreationandcloning.Thisusecaseisespecially

important with vSpheres more ambitious role as a Cloud operating system.

PerformanceManagementEnhancements

Enhanced vCenter Server Scalability

As organizations adopt server virtualization at an unprecedented level, the need to manage large scale

virtual data centers is growing signicantly. To address this, vCenter Server, included with vSphere 4, has been

enhanced to manage up to 300 hosts and 3000 virtual machines. You also have the ability to link many vCenter

Servers in your environment with vCenter Server Linked Mode to manage up to 10,000 virtual machines rom

a single console.

vCenter Performance Charts Enhancements

PerformancechartsinvCenterhavebeenenhancedtoprovideasingleviewofallperformancemetricssuch

asCPU,memory,disk,andnetworkwithoutnavigatingthroughmultiplecharts.Inaddition,theperformance

charts also include the ollowing improvements:

Aggregatedchartsshowhigh-levelsummariesofresourcedistributionthatisusefultoidentifythe

top consumers.

Thumbnailviewsofhosts,resourcepools,clusters,anddatastoresallowforeasynavigationtothe

individual charts.

Drilldowncapabilityacrossmultiplelevelsintheinventoryhelpsin isolatingtherootcauseofperformance

problems quickly.

Detaileddatastorelevelviewsshowutilizat ionbyletypeandunusedcapacity.

ApplicationPerformance

Oracle

VMwaretestinghasshownthatrunningaresource-intensiveOLTPbenchmark,basedonanon-comparable

implementationoftheTPC-C*workloadspecication,OracleDBinan8-vcpuVMwithvSphere4achieved

85percentofnativeperformance.Thisworkloaddemonstrated8,900databasetransactionspersecondand

* The benchmark was a air-use implementation o the TPC-C business model; these results are not TPC-C compliant results, and not comparable to ocial

TPC-C results. TPC Benchmark is a trademark o the TPC.


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60,000diskinput/outputspersecond(IOPS).Theresultsdemonstratedinthisproofpointrepresentthemost

I/O-intensiveapplication-basedworkloadeverruninanX86virtualenvironmenttodate.

2-processor 4-processor 8-processor

3

3.5

4

4.5

2.5

2

1.5

0

0.5

ESX 4

Native

1

ESX 4 Oracle DB VM Throughput,

as Compared to 2-CPU Native Configuration

Figure 9ComparisonoOracleDBVMThroughputvs2-CPUNativeConfguration

The results above were run on a server with only eight physical cores, resulting in an 8-way VM conguration

thatwasnotunder-committingthehost.TheslightlylesscommittedfourvCPUcongurationranat88

percent o native.

SQLServer

RunninganOLTPbenchmarkbasedonanon-comparableimplementationoftheTPC-E*workloadspecication,

aSQLServervirtualmachinewithfourvirtualCPUsonvSphere4.0showed90percenteciencywithrespectto

native.TheSQLServerVMwitha500GBdatabaseperformed10,500IOPSand50Mb/sofnetworkthroughput.

1 cpu 2 cpu

RelativeScalingR

atio

4 cpu

3

4

2

0

Native

VMware VM

1

ESX 4 SQL Server VM Throughput,

as Compared to 1 CPU Native Configuration

Figure 10ComparisonovSphereSQLServerVMThroughputvsNativeConfguration

* The benchmark was a air-use implementation o the TPC-C business model; these results are not TPC-C compliant results, and not comparable to ocial

TPC-C results. TPC Benchmark is a trademark o the TPC.


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SAP

VMwaretestingdemonstratedthatrunningSAPinaVMwithvSphere4scaledlinearlyfromonetoeightvCPUs

perVMandachieved95percentofnativeperformanceonastandard2-tierSAPbenchmark.Thismulti-tiered

applicationarchitectureincludestheSAPapplicationtierandback-endSQLServerdatabaseinstantiatedina

single virtual machine.

1 cpu 2 cpu

Relative

Scalin

gR

atio

4 cpu 8 cpu

6

8

4

0

Native

VMware VM

2

ESX 4 SAP VM Throughput,

as Compared to1 CPU Native Configuration

Figure 11ComparisonoESXSAPVMThroughputvsNativeConfguration

ExchangeMicrosot Exchange Server is one o the most demanding applications in todays datacenters, save the very

largestdatabasesbeingdeployed.PreviousworkonvirtualExchangedeploymentsshowedVMwaresabilityto

improve perormance rom native congurations by designing an Exchange architecture with a greater number

o mailbox instances running ewer mailboxes per instance.

With the perormance enhancements added to vSphere 4 single VM Exchange mailboxes have been

demonstrated at up to 8,000 mailboxes per instance. This means that Exchange administrators will have the

option o choosing the higher perorming smaller mailboxes or the more cheaply licensed large mailbox servers.


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VMware, Inc.HillviewAvenuePaloAltoCAUSATel8-86-2Fax6-2-wwwvmwarecomCopyright9VMware,IncAllrightsreservedThisproductisprotectedbyUSandinternationalcopyrightandintellectualpropertylawsVMwareproductsarecoveredbyoneormorepatentslistedat

http://wwwvmwarecom/go/patentsVMwareisaregisteredtrademarkortrademarkofVMware,IncintheUnitedStatesand/orotherjurisdictionsAllothermarksandnamesmentionedhereinmaybe

1 VM 2 VMs

95percentilelatency(ms)

Users(Thousands)

4 VMs 6 VMs 8 VMs

6

7

8

9

5

4

3

0

1

2

200

250

300

150

100

0

50

Users (thousands) 95 percentile latency

#VCPUs >#PCPUs

ESX 4 Exchange Mailbox Count and Latency

Figure 12vSphereperormanceenhancementswithMicrosotExchange

Summary

VMware innovations continue to make VMware vSphere 4 the industry standard or computing in data centers

o all sizes and across all industries. The numerous perormance enhancements in VMware vSphere 4 enable

organizations to get even more out o their virtual inrastructure and urther reinorce the role o VMware asindustry leader in virtualization.

vSphere represents dramatic advances in perormance compared to VMware Inrastructure 3 to ensure that

even the most resource intensive and scale out applications such as large databases and Microsot Exchange

email systems can run on private clouds powered by vSphere.

References

Performance Evaluation of AMD RVI Hardware Assist

http://www.vmware.com/pdf/RVI_performance.pdf

Performance Evaluation of Intel EPT Hardware Assist

http://www.vmware.com/pdf/Perf_ESX_Intel-EPT-eval.pdf

Documents

VMware vSphere Performance WP En