Figure 7-2 shows a typical three tiered LVS cluster
topology. In this example, the active LVS router routes the requests
from the Internet to the pool of real servers. Each of the real
servers then accesses a shared data source over the network.
This configuration is ideal for busy FTP servers, where accessible
data is stored on a central, highly available server and accessed by
each real server via an exported NFS directory or Samba share. This
topography is also recommended for websites that access a central,
highly available database for transactions. Additionally, using an
active-active configuration with Red Hat Cluster Manager, administrators can configure
one high-availability cluster to serve both of these roles
simultaneously.
The third tier in the above example does not have to use Red Hat Cluster Manager, but
failing to use a highly available solution would introduce a critical
single point of failure.
