Addressing OLTP Solutions with CICS: The Transaction Server ... - Ibm

Client node: The client node contains a CICS client, a workload management
client, a local cache, and a workload management cache manager.
DSOM is not installed on the client node as there is no need to communicate
with the other CICS SM components that use DSOM, namely, the GUI, SMappl,
and WLMAppl-SMappl interface.
The workload management client is called by the CICS client to route the client
request. It does this based on information held in the local cache. The workload
management cache manager manages the local cache, updating it when updates
are received from the WLMAppl or requesting data from the WLMAppl when a
routing request is made for a program or transaction that is not present in the
local cache.
8.5 Workload Management Considerations
8.5.1 Maximizing the Benefit
In this section we look more closely at three aspects of workload management.
First we examine the sort of configurations that are required to improve the
value that can be obtained from introducing workload management. Second we
look the reference system that is used with workload management in order to
rank the size of different processors in a CICS configuration. Third we look at
the workload management algorithm.
Workload management is most effective when there are a number of CICS
systems from which to choose. There is little point in implementing workload
management with a single CICS system, unless you are planning to
subsequently expand, as there is only the one system to which to route. Static
routing would be just as effective in such a case.
8.5.1.1 Combining Resources
The ideal approach for workload management is to have one (or more)
applications available with each CICS system on its own machine. It may be that
you choose to adopt this approach for only your most critical applications. There
could be significant value, however, in combining several less obvious
candidates for workload management and the machines on which they run. The
aim is to provide one common type of CICS system that contains all of the
resources required to run each of the applications. This common CICS system is
then reproduced on multiple systems. Workload management is used to
distribute the incoming work over the systems that can process the work. Such
an approach can provide benefits to each of the applications as the combined
machine resources are now available for the applications. Such an environment
cannot proceed without the use of effective workload management. The
availability of CICS SM workload management now enables you to adapt in the
distributed transaction processing world.
Consider the case shown in Figure 38 on page 122.
Chapter 8. Using CICS System Manager for AIX 121