Installation guide

Chapter 1. Red Hat Cluster Suite Overview 27
of the active LVS router. During failover, the backup LVS router takes over the VIP ad-
dresses serviced by the failed router using a technique known as ARP spoofing — where
the backup LVS router announces itself as the destination for IP packets addressed to the
failed node. When the failed node returns to active service, the backup LVS router assumes
its backup role again.
The simple, two-tier configuration in Figure 1-20 is suited best for clusters serving data
that does not change very frequently — such as static web pages — because the individual
real servers do not automatically synchronize data among themselves.
1.8.2. Three-Tier LVS Topology
Figure 1-21 shows a typical three-tier LVS configuration. In the example, the active LVS
router routes the requests from the public network (Internet) to the second tier — real
servers. Each real server then accesses a shared data source of a Red Hat cluster in the
third tier over the private network.