78 IBM Branch Transformation Toolkit 5.1 Migration and Usage Guidelines
The Web server contains the application resources needed by the browser.
In a Java client topology, the proxy server is not required because Java clients do
not have the same features as Web browsers.
3.3 Workload management decisions
While not strictly related to migration activities, certain implications of Workload
Management (WLM) can affect migration planning. These are mostly related to
test and deployment activities.
Workload management is the process of spreading multiple requests for work
over the resources that can do the work. It optimizes the distribution of
processing tasks in a WebSphere Application Server environment. It also
improves performance, scalability, and availability of systems and applications,
besides providing failover when servers are not available.
Workload management is most effective when the deployment topology
comprises application servers on multiple machines, since such a topology
provides both failover and improved scalability. It can also be used to improve
scalability in topologies where a system comprises multiple servers on a single,
high-capacity machine. In either case, it enables the system to effectively use the
available computing resources.
WLM provides the following benefits when constructing applications:
It balances client requests, allowing incoming work requests to be distributed
according to a configured WLM selection policy.
It provides failover capability by redirecting client requests to a running server
when one or more servers are unavailable. This improves the availability of
applications and administrative services.
It enables systems to be scaled up to serve a higher client load than that
provided by basic configuration. With clusters and cluster members,
additional instances of servers can easily be added to the configuration.
It enables servers to be transparently maintained and upgraded while the
applications remain available for users.
It centralizes the administration of application servers and other objects.