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.
Figure 7-2. A Three Tiered LVS Configuration
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.