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

► Horizontal scaling
Horizontal scaling involves creating application servers on multiple machines
to take advantage of the additional processing capacity available on each
machine. Using horizontal scaling techniques also provides hardware failover
support.
The following components provide functions for configuring scalability:
► WebSphere Application Server cluster support
The use of application server clusters can improve the performance of a
server, simplify its administration, and enable the use of workload
management.
► WebSphere workload management
The workload management capabilities of WebSphere Application Server can
be used to distribute requests among converged containers and EJB
containers in clustered application servers. This enables both load balancing
and failover, improving the reliability and scalability of WebSphere
applications. On the z/OS platform, the workload management function is
tightly integrated with the operating system to take advantage of the superior
workload management features of z/OS.
► IP sprayer
The IP sprayer transparently redirects all incoming HTTP requests from Web
clients to a group of Web servers. Although the clients behave as though they
are communicating directly with one specific Web server, the IP sprayer is
actually intercepting all those requests and distributing them among all the
available Web servers in the group. IP sprayers (such as the Load Balancer
Edge component or Cisco Local Director) can provide scalability, load
balancing, and failover for Web servers and other TCP/IP-based servers
whose protocol is understood by the IP sprayer.
5.1.6 Application deployment
Various application deployment decisions affect topology decisions. The
following application deployment-related considerations should be clarified
before finalizing the architecture.
Deployment of your EJBs
The way you deploy your EJBs will have a significant impact on your application
topology and of the performance you can expect. You have the choice to deploy
EJBs to the same application servers and clusters as the client modules invoking
the EJBs, or to separate, dedicated application servers and clusters running the
EJBs only.
Chapter 5. Topologies 129