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Table Of Contents
VMware Server User’s Guide
196 VMware, Inc.
Starting a Virtual Machine Repeatedly in the Same State
Youcanconfigureavirtualmachinetoreverttoasnapshotanytimeitispoweredoff,
asdescribedin“SettingSnapshotPowerOffOptions”onpage 127.Forexample,you
mightusethisfeaturewhensettingupstudentvirtualmachinessothatyoucanstart
eachnewclassatthebeginning
ofthelesson,discardingthepreviousstudent’swork.
What Is Captured by a Snapshot
Asnapshotcapturestheentirestateofthevirtualmachineatthetimeyoutakethe
snapshot.Thisincludes:
MemorystateContentsofthevirtualmachine’smemory.
ConfigurationstateVirtualmachinesettings.
DiskstateStateofthevirtualmachine’svirtualdisks.
Whenyoureverttoasnapshot,youreturnthevirtualmachine’smemory,settings,and
diskstothestatetheywereinwhenyoutookthesnapshot.Ifyouwantthevirtual
machinetobesuspended,poweredon,orpoweredoffwhen
youlaunchit,besureitis
inthestateyouwantwhenyoutakethesnapshot.
Activities That Conflict with Snapshots
Whenyoutakeasnapshot,beawareofotheractivitygoingoninthevirtualmachine
andthelikelyimpactofrevertingtothatsnapshot.Ingeneral,itisbesttotakea
snapshotwhennoapplicationsinthevirtualmachinearecommunicatingwithother
computers.Thepotentialforproblemsis
greatestifthevirtualmachineis
communicatingwithanothercomputer,especiallyinaproductionenvironment.
Consideracaseinwhichyoutakeasnapshotwhilethevirtualmachineisdownloading
afilefromaserveronthenetwork.Afteryoutakethesnapshot,thevirtualmachine
continuesdownloadingthefile,communicating
itsprogresstotheserver.Ifyourevert
tothesnapshot,communicationsbetweenthevirtualmachineandtheserverarelost
andthefiletransferfails.
Orconsideracaseinwhichyoutakeasnapshotwhileanapplicationinthevirtual
machineissendingatransactiontoadatabaseon
aseparatemachine.Ifyourevertto
thatsnapshotafterthetransactionstartsbutbeforeithasbeencommitted,thedatabase
couldbeinconsistent.
N
OTEThestateoftheindependentdisksisnotpreservedwhenyoutakea
snapshot.See“ExcludingVirtualDisksfromSnapshots”onpage 198.