5.5

QuickStart Guide
10 VMware, Inc.
Figure 1-4. Communication between Primary and Secondary Servers
The IP address a client uses to connect to the active server (the Principal (Public) IP address) must be
configured as a static IP address (not DHCP enabled). In the example in Figure 1-4, the IP address is
configured as 192.168.1.127.
The Principal (Public) NICs on the passive server are configured to use the same IP address as that of the active
server but are prevented from communicating with the live network through an IP packet filtering system
installed with vCenter Server Heartbeat. This packet filter prevents traffic using the Principal (Public) address
from being committed to the wire. It also prevents NetBIOS traffic utilizing other IP addresses on the NIC from
being sent to prevent NetBIOS name resolution conflicts.
The NICs on the active and passive servers used for the VMware Channel are configured so that their IP
addresses are outside of the Principal (Public) networks subnet range. These addresses are termed the
VMware Channel addresses.
Following the restore and after the vCenter Server Heartbeat installation completes (runtime), NetBIOS is
disabled across the channel(s). This occurs during installation to prevent a name conflict, which occurs when
both servers have the same name.
The NICs that support connectivity across the VMware Channel can be standard 100BaseT Ethernet cards
providing a throughput of 100Mbits per second across standard Cat-5 cabling.
When configured for a WAN deployment, the VMware Channel uses static routes over switches and routers
to maintain continuous communications independent from corporate or public traffic.
vCenter Server Heartbeat software is installed on a Primary server and a Secondary server. These names refer
to the physical hardware (identity) of the servers.
The Secondary server has the same name, same file and data structure, same network address, and can run all
the same applications and services as the Primary server.
Only one server name and network address can be visible on the same network at any one time. One of these
two servers is live on the Principal (Public) network and serves the protected applications. This is the active
server. The other server is hidden from the Principal (Public) network, remains as a ready standby server, and
is the passive server.
The vCenter Server Heartbeat software is symmetrical in almost all respects, and either the Primary Server or
the Secondary server can take the active role and provide the protected application to users.