WebSphere Application Server V7.0: Concepts ... - IBM Redbooks

5.3.3 Horizontal scaling topology
User
Horizontal scaling means to create one logical unit of servers across multiple
systems or LPARs where each member of the unit is able to serve each request.
Horizontal scaling at the application server tier does not require an IP sprayer. If
you want to scale at the Web server tier as well, we suggest that you implement
an IP sprayer.
We first introduce a topology without an IP sprayer and then one with the IP
sprayer component (see“Horizontal scaling topology with an IP sprayer” on
page 150).
Horizontal scaling topology without an IP sprayer
The topology shown in Figure 5-4 lets a single application span multiple
machines, while presenting itseft as a single logical image. In this example, the
WebSphere Application Server cluster spans System B and System C, each with
one application server. The deployment manager is installed on a separate
server, System D.
Outsid e Wo rld DMZ Internal Network
I
N
T
E
HTTP/HTTPS
R
N
E
T
Protocol Firewall
Web Server
Figure 5-4 Horizontal scaling with cluster
Plug-in
System A
Domain Firewall
Application
Server 1
Cluster
System B
Application
Server 2
System C
System D
Deployment
Manager
Directory
and Security
Services
Existing
applications
and data
Chapter 5. Topologies 147