Specifications

Basic System Administration
250 VMware, Inc.
Whenyoureverttoasnapshot,youreturnalltheseitemstothestatetheywereinatthe
timeyoutookthatsnapshot.Ifyouwantthevirtualmachinetobesuspended,powered
on,orpoweredoffwhenyoulaunchit,besureitisinthecorrectstatewhen
youtake
thatsnapshot.
Snapshotsareusefulwhenyouneedtorevertrepeatedlytothesamestatebutyoudon’t
wanttocreatemultiplevirtualmachines.Withsnapshots,youcreatebackupand
restorepositionsinalinearprocess.Youcanalsopreserveabaselinebeforediverging
avirtualmachineina
processtree.
Snapshotscanbeusedasrestorationpointsduringalinearoriterativeprocess,suchas
installingupdatepackages,orduringabranchingprocess,suchasinstallingdifferent
versionsofaprogram.Takingsnapshotsensuresthateachinstallationbeginsfroman
identicalbaseline.
Multiplesnapshotsreferstotheabilityto
createmorethanonesnapshotofthesame
virtualmachine.Totakesnapshotsofmultiplevirtualmachines,(forexample,
snapshotsforallmembers ofateam)requiresthatyoutakeaseparatesnapshotofeach
teammember.
Multiplesnapshotsarenotsimplyanewwayofsavingyourvirtualmachines.With
multiplesnapshots,youcansavemanypositionstoaccommodatemanykindsofwork
processes.
(S EE U PDATE ) Althoughyoucantakesnapshotsupto32levels,theamountoftimeit
takestocommitordeletethosesnapshotsincreasesasthelevelsgetdeeper.The
requiredtimeisdirectlyproportionaltotheamountofdata(committedordeleted)and
thevirtualmachine’sRAMsize.
Relationship Between Snapshots
Therelationshipbetweensnapshotsislikethatofaparenttoachild:
 Inthelinearprocess,eachsnapshothasoneparentandonechild,exceptforthe
lastsnapshot,whichhasnochildren.
 Intheprocesstree,eachsnapshothasoneparent,butonesnapshotmayhave
morethanonechild.Manysnapshotshavenochildren.
Youcanreverttoaparentorachild.