Specifications

Basic System Administration
240 VMware, Inc.
Aspecifichostfeature’seffectsoncompatibilityaredependentonwhetherornotESX
Serverexposesorhidesthemfromvirtualmachines:
 Featuresthatareexposedtovirtualmachinesarenotcompatiblewhentheyare
mismatched.
 Featuresthatarenotexposedtovirtualmachinesarecompatibleregardlessof
mismatches.
CPU Compatibility Masks
VirtualCentercomparestheCPUfeaturesoftwohoststodeterminewhethertoallow
ordisallowmigrationswithVMotion.AnewcapabilityinVirtualCenter2.0calledCPU
compatibilitymasksallowsper‐virtualmachine,advancedcustomizationoftheCPU
featuresthatavirtualmachineshouldrequireforCPUcompatibilityduringa
migrationwith
VMotion.
 DefaultvaluesfortheCPUcompatibilitymasksaresetbyVMwaretoguarantee
thestabilityofvirtualmachinesafteramigrationwithVMotion.Changestothese
defaultmasksaremadeveryconservativelybyVMware,andonlywhennewCPU
featuresareintroducedandversionsofESXServerareupdatedtoexpose
orhide
themfromvirtualmachines.
 Insomecases,whereachoicebetweenCPUcompatibilityorguestoperating
systemfeatures(suchasNX/XD)exists,VMwareprovidescheck‐boxoptionsto
configureindividualvirtualmachinesthroughthevirtualmachine’sAdvanced
Settingsoption.Advancedvirtualmachinevirtualhostmodificationscanbeused
bydevelopers.
N
OTEEditingavirtualmachine’sCPUcompatibilitymaskissupportedinESXServer
3.xonly.
Choose between Nx/xD
Security features or Broadest
VMotion Compatibility
For future CPU features, edit
mask at the bit level