Specifications

Copyright © 2008 VMware, Inc. All rights reserved. 8
Installing and Configuring Linux Guest Operating Systems
Major Components Installed by VMware Tools
ThemajorcomponentsofVMwareToolswheninstalledincludevmblock,vmdesched(tobedeprecatedin
upcomingreleasesofVMwareTools),vmhgfs,vmmemctl,vmsync,andvmxnet.Thissectiontakesacloserlook
atvmxnet,thecomponentofmostinteresttoLinuxadministrators.
vmxnet
vmxnetisaLinuxkerneldevicedriverfortheVMwarehigh‐speedvirtualnetworkingdevice.Thenetwork
devicesinavirtualmachinearebasedonrealhardware.Forexample,vlanceisavirtualdevicethatprovides
strictemulationoftheAMDLancePCNet32Ethernetadapterfor32‐bitguests,ande1000
isavirtualdevice
thatprovidesstrictemulationoftheIntelE1000Ethernetadapterfor32‐bitand64‐bitguests.Whencreatinga
32‐bitvirtualmachine,ifyouselectFlexibleasthenetworkadapter,thevirtualmachinedefaultstovlance
beforeVMwareToolsisinstalledbutswitchesto
vmxnetafterVMwareToolsisinstalled.Whencreatinga
64‐bitvirtualmachine,ifyouselectE1000asthenetworkadapter,thevirtualmachineusese1000asthe
networkadapterregardlessofwhetherVMwareToolsisinstalled.
Alternatively,forsome32‐and64‐bitguests,youcanselectEnhancedvmxnetas
thenetworkadapter .vmxnet
isspecificallydesignedforvirtualmachinestoimproveperformance.EnhancedVMXNET,introducedinESX
3.5,providesanewversionofthevmxnetvirtualdevice(theVMwareparavirtualizedvirtualnetworking
deviceforguestoperatingsystems).EnhancedVMXNETincludesseveralnewnetworkingI/Operformance
improvements,suchassupportfor
TCP/IPsegmentationoffload(TSO)andjumboframes.Allother
networkingfeatures,suchasteamingandVLANs,arefullysupported.ToenableTSOandjumboframes,see
theESXServer3ConfigurationGuide.Foralink,see“Resources”onpage 19.Youcanalsousethecommand
lineinterfacetoconfigureMTU
(maximumpacketsize)andtoenableordisableTSO.EnhancedVMXNETis
notsupportedonevery32‐and64‐bitLinuxdistribution,butiftheoptionexists,werecommendyouselect
EnhancedVMXNETasyournetworkadapterforbetterperformance.ThisisespeciallytrueonIntelVT‐x
systemswhere
VMEXITcostsarehigh.vmxnethasalowerrateofVMEXITscomparedwithe1000.
EnhancedVMXNETissupportedforonlythefollowingLinuxguestoperatingsystems:
 RedHatEnterpriseLinux5(32and64bit)
 RedHatEnterpriseLinux4(64bit,nojumboframesupport)
 SUSELinuxEnterpriseServer10(32and64bit)
Experimentalsupportisprovidedfor:
 RedHatEnterpriseLinux3(64bit,noTSO,nojumboframesupport)
 SUSELinuxEnterpriseServer9(64bit,nojumboframesupport)
 Ubuntu7.04(64bit,nojumboframesupport)
Becauseitisbackedbyactualvirtualhardware,EnhancedVMXNETshouldbeloadedautomaticallyby
hotplugorudevasneeded.Forbestperformance,werecommendthatyouenableTSOonallinterfacesdriven
byvmxnetusingethtool.
ToenableTSO,useshellcode
similartothefollowing:
if which ethtool >/dev/null 2>&1; then
for ethif in `ifconfig -a | grep ^eth
| cut -d' ' -f1`; do
ethtool -K $ethif tso on >/dev/null 2>&1
done
fi
VMware Tools Upgrades
YoucanupgradeVMwareToolsmanually,oryoucanconfigurevirtualmachinestocheckforandinstall
newerversionsofVMwareToolsautomatically.Thefollowingarerequiredforautomaticupgrades:
 VirtualmachinesmusthaveaversionofVMwareToolsshippedwithESXServer3.0.1orgreaterinstalled.