Specifications

VMware, Inc. 153
Chapter 10 Creating Virtual Machines
Mapping a SAN LUN
ForvirtualmachinesrunningonanESXServerhost,insteadofstoringvirtualmachine
datainavirtualdiskfile,youcanstorethedatadirectlyonaSANLUN.Thisisuseful
ifyouarerunningapplicationsinyourvirtualmachinesthatmustknowthephysical
characteristicsofthestorage
device.
WhenyoumapaLUNtoaVMFSvolume,VirtualCentercreatesafilethatpointstothe
rawLUN.EncapsulatingdiskinformationinafileallowsVirtualCentertolockthe
LUNsothatonlyonevirtualmachinecanwritetoit.
To map a SAN LUN
1FromtheSelectaDiskpage,selectMapped
SANLUN.
2ClickNext.
3 SelectaLUNfortherawdisk.
4ClickNext.
5 SelectadatastoreontowhichtomaptheLUN.
6ClickNext.
7 Selectacompatibilitymode,eitherphysicalorvirtual.
 Physicalcompatibilitymodeallowstheguestoperatingsystemtoaccessthe
hardwaredirectly.PhysicalcompatibilityisusefulifyouareusingSAN‐aware
applicationsinthevirtualmachine.However,aLUNconfiguredforphysical
compatibilitycannotbecloned,madeintoatemplate,ormigratedifthe
migrationinvolvescopyingthedisk.

 VirtualcompatibilitymodeallowsthevirtualmachinetouseVMware
snapshotsandotheradvancedfunctionality.Virtualcompatibilityallowsthe
LUNtobehaveasifitwereavirtualdisk,soyoucanusefeatureslikedisk
modes.Whenyouclonethedisk,makeatemplateoutofit,ormigrateit
(ifthe
migrationinvolvescopyingthedisk),thecontentsoftheLUNarecopiedinto
avirtualdisk(.vmdk)file.
Subsequentscreensofferdifferentoptions,dependingonyourchoice.
N
OTEThisfilehasa.vmdkextension,butthefilecontainsonlydiskinformation
describingthemappingtotheLUNontheESXServersystem.Theactualdataisstored
ontheLUN.
YoucannotdeployavirtualmachinefromatemplateandstoreitsdataonaLUN;you
canonly
storeitsdatainavirtualdiskfile.