How it works: CICSPlex SM workload management (WLM)

Typically, if you run more than three or four AORs, you can benefit from using CICSPlex® SM WLM to manage workloads. In the context of CICSPlex SM, workload management (WLM) means ensuring that, when a transaction arrives in a CICS region or when a program is linked-to from a CICS region, the most optimal CICS region is dynamically selected and the work is routed to that region to be run.

This section introduces the key concepts of CICSPlex SM WLM and a high-level view of what is involved in setting up CICSPlex SM WLM.

Setting up CICSPlex SM WLM

Let's look at who is involved in setting up CICSPlex SM WLM. Figure 1 shows the basic topology.
  • The software architect determines the goals for workload management and determines any constraints to be applied to specific workloads: for example, separating - or linking - certain types of work.
  • The software architect identifies the work requests that are eligible for dynamic routing using CICSPlex SM WLM.
  • The system administrator configures the components of CICSPlex SM, using either CICS Explorer or the CICSPlex SM WUI. The system administrator creates groups of CICS regions to participate in CICSPlex SM workload management, and specifies how each workload will be managed.
Figure 1. Basic topology of CICSPlex SM WLM
Image described in surrounding text

Requests for work to be managed by CICSPlex SM WLM are made from a region in a CICSplex.

A specification for each workload defines the CICS systems to be treated as routing regions and the target regions for processing the workload. Workload management rules provide the granularity that is needed to handle special workload conditions: for example, making sure that certain types of work are separated from each other, or for maintaining relationships (affinities) between certain types of work.

CICSPlex SM uses dynamic routing, so a routing program is needed to decide where to run a piece of work. In CICSPlex SM, the user-replaceable dynamic routing program EYU9XLOP provides this function,

Routing algorithms provided by CICSPlex SM WLM take into account a complex array of factors to select the optimal region for processing the incoming work request. These factors include:
  • How loaded the available CICS regions are.
  • How healthy the available CICS regions are.
  • How responsive the available CICS regions are.
  • Where the available CICS systems are and how they are connected.

The work is passed to one or more target regions for processing.

CICSPlex SM workload management: find the information that you'll need

To work with CICSPlex SM WLM, you'll need the following parts of the IBM Knowledge Center.
Table 1. Where's the information about CICSPlex SM WLM?
Topic Where to look
Find out what you need to consider about your workload before you can manage it with CICSPlex SM WLM Workload considerations
Find out your options for routing work between regions Routing considerations
Find out how CICSPlex SM WLM works Components of CICSPlex SM WLM and How CICSPlex SM WLM routes work
Set up CICSPlex SM WLM Creating workload management definitions and Workload management tasks
Manage workloads in CICS Explorer Managing workloads in the CICS Explorer product documentation