6.3

Table Of Contents
VMware, Inc. 15
Chapter 1 Introduction
Figure 1-2. Switchover
Aswitchovergracefullyclosesanyprotectedapplicationsthatarerunningontheactiveserverandrestarts
themonthepassiveserver,includingtheapplicationorservicethatcausedthefailure.Intheexamplewhere
thePrimaryserverisactiveandtheSecondaryserverispassive,thePrimaryserverisdemoted
toapassive
roleandishiddenfromthenetworkwhentheSecondaryserverispromotedtoanactiveroleandismade
visibletothenetwork.Themechanicsofswitchoversarediscussedinmoredetaillaterinthisguide.
Performance Protection
Ensuringthatyourprotectedapplicationsareoperationalandprovidingserviceatalevelofperformance
adequateforuserstoremainproductiveisimportant.ThevCenterServerHeartbeatpluginprovidesthese
monitoringandpreemptiverepaircapabilities.
vCenterServerHeartbeatproactivelymonitorssystemperformanceattributestoensurethatthesystem
administrator
isnotifiedofproblemsandcantakepreemptiveactiontopreventanoutage.
Inadditiontomonitoringapplicationservices,vCenterServerHeartbeatcanmonitorspecificapplication
attributestoensurethattheyremainwithinnormaloperatingranges.Similartoapplicationmonitoring,
variousrulescanbeconfiguredtotriggerspecificcorrectiveactions
whenevertheseattributesfalloutsideof
theirrespectiveranges.
vCenterServerHeartbeatprovidesthesamelevelofflexibilitytodefineandperformmultiplecorrective
actionsintheeventofproblemsonaservicebyserviceorevenattributebyattributebasis.
Data Protection
YoucanconfigurevCenterServerHeartbeattoprotecttheapplicationenvironment.Alldatafilesthatusersor
theapplicationsrequireintheapplicationenvironmentaremadeavailableshouldafailureoccur.After
installation,vCenterServerHeartbeatconfiguresitselftoprotectfiles,folders,andregistrysettingsfor
vCenterServerontheactive
serverbymirroringtheminrealtimetothepassiveserver.Ifafailoveroccurs,all
filesprotectedonthefailedserverareavailabletousersafterthefailover,hostedontheSecondaryserver.
vCenterServerHeartbeatinterceptsallfilesystemI/Ooperationsontheactiveserver.Iftheinterceptedwrite
andupdateoperationsarewithintheprotectedset,theseareplacedinaqueueontheactiveserverreferredto
astheactiveserverssendqueue,pendingtransmissiontothepassiveserver.Eachrequestisnumberedto
maintainitsorderinthequeue.
Withtherequestintheactiveserverssend
queue,vCenterServerHeartbeatallowsthediskI/Otocontinue
withtherequesteddiskoperation.
Ifthechannelisconnected,theactiveserverssendqueueistransferredtothepassiveserver,whichplacesall
therequestsinthepassiveserversreceivequeue.Thepassiveserverconfirmsthechangeswereloggedby
sendingtheactiveserveranacknowledgement.Theactiveserverclearsthedatafromitsqueue.