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Chapter 3 Server Protection
ThisisparticularlyusefulwhenmaintenanceworkperformedonthePrimaryserverrequiresrebootingthe
server.
Sinceamanagedswitchovercannotbeperformedduringsynchronization,itisimportanttoreviewthequeue
informationpriortoattemptingamanagedswitchover.Ifthequeuesarelarge,fileoperationsontheactive
serverare
highandforthisreasonitmaybeprudenttodelayamanagedswitchoverduetothelengthoftime
requiredtocompletelyclearthequeue.QueuelengthscanbeviewedintheData:Traffic/Queuespageofthe
vCenterServerHeartbeatConsole.
PriortoperformingworkonthePrimaryserver,a
managedswitchovercanbetriggeredbyselectingthe
SecondaryserverandclickingMakeActiveontheServer:Summarypage.Thischangestheserverrolessuch
thattheactiveserverbecomespassiveandthepassiveserverbecomesactive.Thismeansusersareableto
workcontinuouslywhilethePrimaryserverisoff
line.
WhenthePrimaryserverisbackupandrunning,themanagedswitchovercanbetriggeredagainsothatthe
Primaryserverbecomesactiveandthepreviouslyactiveserverbecomespassive.
Recovering From a Failover
Afailoverdiffersfromaswitchover.Aswitchoverisacontrolledswitch(initiatedmanuallyfromthevCenter
ServerHeartbeatConsole,orinitiatedbyvCenterServerHeartbeatwhenpreconfigured)betweentheactive
andpassiveservers.Afailoverhappenswhenanyofthefollowingfailontheactiveserver:power,hardware,
orVMware
Channelcommunications.Thepassiveserverwaitsapreconfiguredtimeafterthefirstmissed
heartbeatbeforeinitiatingafailover.Whenthisperiodexpires,thepassiveserverautomaticallyassumesthe
activeroleandstartstheprotectedapplications.
ThefollowingrecoveryscenarioisbasedonvCenterServerHeartbeatconfigurationwiththePrimaryserver
as
activeandtheSecondaryserveraspassive.
AfailoverhasoccurredandtheSecondaryserverisnowrunningastheactiveserver.
1Revieweventlogsonbothserverstodeterminethecauseofthefailover.Forassistance,usetheLog
CollectortooltocollectinformationandsendtheoutputtoVMware
Support.
2IfanyofthefollowingissuesexistonthePrimaryserver,performingaswitchbacktothePrimaryserver
maynotbepossibleuntilotherimportantactionsarecarriedout.DonotrestartvCenterServerHeartbeat
untilthefollowingissueshavebeenresolved:
HardDiskFailureReplacethedefectiveharddisk.
PowerFailureRestorepowertothePrimaryserver.
VirusCleantheserverofallviruses.
CommunicationsReplaceorrepairthephysicalnetworkhardware.
BlueScreenDeterminecauseandresolve.Asrequired,submitthedumpfiletoVMwareSupport
(www.vmware.com/support)foranalysis.
3RuntheConfigureServerwizardandverifytheserveridentityissettoPrimaryandtheroleissetto
passive.ClickFinishtoacceptthechanges.
4DisconnecttheVMwareChannelnetwork
cablesordisablethenetworkcard.
5Resolvethelistofpossiblefailures.
6Restartthisserverandreconnectorenablethenetworkcardagain.
I
MPORTANTThemanagedswitchoverprocessmaybeperformedatanytimeaslongasthesystemsarefully
synchronizedwithrespecttodatafilesandregistryreplication.Switchoverscannotbeperformedifeitherserveris
inanunsynchronizedorunknownstate.
NOTEWhenfailoverconditions,suchasapowerfailure,causefailuresinbothactiveandpassiveservers,a
conditionmayresultthatcausesbothserverstorestartinpassivemode.Inthissituation,manualintervention
isrequired.SeeAppendix 10,“TwoPassiveServers,”onpage 67.