6.3

Table Of Contents
VMware, Inc. 17
Chapter 1 Introduction
Whendeployedwithidenticalnodes,thePrincipal(Public)NICsonthepassiveserverareconfiguredtouse
thesameIPaddressasthatoftheactiveserverbutarepreventedfromcommunicatingwiththelivenetwork
throughanIPpacketfilteringsysteminstalledwithvCenterServerHeartbeat.Thispacketfilterprevents
trafficusingthePrincipal(Public)addressfrombeingcommittedtothewire.ItalsopreventsNetBIOStraffic
utilizingotherIPaddressesontheNICfrombeingsenttopreventNetBIOSnameresolutionconflicts.
TheNICsontheactiveandpassiveserversusedfortheVMwareChannelareconfiguredsothattheir
IP
addressesareoutsideofthesubnetrangeofthePrincipal(Public)network.Theseaddressesare referredtoas
VMwareChanneladdresses.
Duringinstallation,setupwillswitchoffNetBIOSfortheVMwareChannel(s)ontheactiveandpassive
serversasthisconnectionremainsliveandboththepassiveandactivemachines
havethesameNetBIOS
name.FollowingrestoreandafterthevCenterServerHeartbeatinstallationcompletes(runtime),NetBIOSis
disabledacrossthechannel(s).Thisoccursduringinstallationtopreventanameconflict,whichoccurswhen
bothservershavethesamename.
TheNICsthatsupportconnectivityacrosstheVMwareChannelcanbe
standard100BaseTEthernetcards
providingathroughputof100MbitspersecondacrossstandardCat5cabling.Initsmostbasicform,a
dedicatedchannelrequiresnohubsorrouters,butthedirectconnectionrequirescrossovercabling.
WhenconfiguredforaWANdeployment,configuretheVMwareChanneltousestaticroutes
overswitches
androuterstomaintaincontinuouscommunicationsindependentfromcorporateorpublictraffic.
vCenter Server Heartbeat Switchover and Failover Processes
vCenterServerHeartbeatusesfourdifferentproceduresmanagedswitchover,automaticswitchover,
automaticfailover,andmanagedfailovertochangetheroleoftheactiveandpassiveserversdependingon
thestatusoftheactiveserver.
Managed Switchover
YoucanclickMakeActiveonthevCenterServerHeartbeatConsoleServer:Summarypagetomanually
initiateamanagedswitchover.Whenamanagedswitchoveristriggered,therunningofprotected
applicationsistransferredfromtheactivemachinetothepassivemachineintheserverpair.Theserverroles
arereversed.
Figure 1-5.
Switchover
Amanagedswitchoverperformsthefollowingsteps:
1Stoptheprotectedapplicationsontheactiveserver.Aftertheprotectedapplicationsstop,nomoredisk
updatesaregenerated.
2Sendallupdatesthatarestillqueuedontheactiveservertothepassiveserver.Afterthisstep,allupdates
areavailableonthepassive
server.