Defining z/OS WLM classification rules for performance policies from the Unified Resource Manager

For virtual servers that run z/OS®, you can map service classes from a Unified Resource Manager performance policy to z/OS WLM service classes to achieve end-to-end goal-based performance management for multitier applications. Through classification rules for the IBM-defined EWLM subsystem type, z/OS WLM administrators can assign work requests that originate from virtual servers in an ensemble workload to service classes and report classes on z/OS.

The EWLM subsystem work requests include DB2® distributed data facility (DDF) requests that originate from an ensemble, through virtual servers (or hosts) that are classified within a Unified Resource Manager performance policy. Unified Resource Manager performance policies have service classes that specify either discretionary or velocity performance goals that the Unified Resource Manager uses to manage virtual servers in the ensemble workload. When you correlate these zEnterprise service classes to WLM service classes, you enable z/OS WLM to manage the work differently than it does for local z/OS work:

z/OS WLM assigns the incoming work request to the appropriate WLM service class immediately, instead of going through the z/OS classification process.
z/OS WLM can manage the work processed by a z/OS subsystem, such as DDF, according to different performance goals than those used for local z/OS work.
z/OS WLM also can assign the work requests originating from virtual servers in the ensemble to different report classes than those used for local z/OS work.

The configuration tasks necessary for mapping zEnterprise service classes to WLM services classes are described in the following. Ensemble workload administrators, performance management administrators, and z/OS WLM administrators collaborate to complete these tasks.

For the ensemble, perform the following steps:

Create a workload and add the z/OS virtual servers to it. Also enable guest platform management provider (GPMP) support for each z/OS virtual server.
Define policies, service classes, and classification rules for the workload, and schedule activation of the appropriate policy. Note that z/OS WLM restricts the length of service class names to 32 characters, so you need to observe this restriction when you define the names of zEnterprise service classes that you want to map to WLM service classes.
Configure and activate a guest platform management provider on virtual servers that support the tiers of a multitier application. Also enable application response measurement (ARM) for the IBM® middleware running on those virtual servers.
Depending on the configuration requirements of the multitier applications that your company uses, you might need to configure guest platform management providers and enable ARM for middleware not only on the virtual servers running z/OS, but also on z/VM® guests and virtual servers on a POWER® blade.

For z/OS images running on virtual servers, perform the following steps:

For each Unified Resource Manager workload that contains virtual servers running z/OS:
- Decide whether corresponding WLM service classes are required for the service classes within the Unified Resource Manager performance policy. If so, define the new WLM service classes that set only response time goals for Unified Resource Manager work requests. These response time goals apply to all DB2 distributed data facility (DDF) requests that originate from ensemble virtual servers that are classified within a performance policy from the Unified Resource Manager.
- Optionally, define one WLM service class as the default service class for work associated with a Unified Resource Manager workload policy.
To map zEnterprise service classes to their corresponding WLM service classes, modify the classification rules for the EWLM subsystem type. Use only the ESC work qualifier in the classification rules.
Optionally, specify WLM report classes to monitor the performance of Unified Resource Manager work requests separately from local z/OS work.

To map specific zEnterprise service classes to WLM service classes, you need to know the names of the zEnterprise service classes and the performance goals that they set. For example, suppose that a Unified Resource Manager performance policy defines performance goals for Internet sales. Within that policy is a service class named WebSales, containing classification rules that identify ensemble virtual servers that send work requests to z/OS images. For those virtual servers, the WebSales service class sets the business importance as high and the velocity goal as fast.

On z/OS, suppose that the z/OS WLM administrator defines two new WLM service classes for the work requests that arrive from z/OS virtual servers in the ensemble: ZMGRDEFA is the default service class for most work and GPFASTHI is the corresponding service class for the WebSales service class. Through these two WLM service classes, the z/OS WLM administrator defines different response time goals for the work requests that arrive from virtual servers in the same ensemble as the z/OS virtual servers.

To map the new WLM service classes to the zEnterprise service classes, the z/OS WLM administrator modifies the classification rules for the EWLM subsystem type. Figure 1 illustrates a sample WLM ISPF panel through which you map zEnterprise service classes to the corresponding WLM service classes:

Figure 1. Sample z/OS WLM Classification Rules Panel for Mapping Unified Resource Manager performance policies

 Subsystem-Type  Xref  Notes  Options  Help
 --------------------------------------------------------------------------
                  Modify Rules for the Subsystem Type     Row 3 to 10 of 16
 Command ===> ____________________________________________ SCROLL ===> PAGE

 Subsystem Type . : EWLM        Fold qualifier names?   N  (Y or N)
 Description  . . . Rules based on E2E classif. data

 Action codes:   A=After     C=Copy        M=Move     I=Insert rule
                 B=Before    D=Delete row  R=Repeat   IS=Insert Sub-rule
                                                              More ===>
           --------Qualifier--------               -------Class--------
 Action    Type       Name     Start                Service     Report
                                          DEFAULTS: ZMGRDEFA    ZMGRREPT
  ____  1  ESC        WebSales 1                    GPFASTHI    ________
  ____  1  ESC        StoreSal 1                    GPFSTHST    ________
  ____  3    ESC        es       9                  ________    ________

On the left side of the panel, note the values under the Qualifier heading:

In the Type column, ESC is the required work qualifier that you must use for the EWLM subsystem type.
In the Name column, the names of several zEnterprise service classes are displayed. WebSales is at the top of the list. The entry for StoreSales illustrates how to enter a zEnterprise service class name that is longer than eight characters.

On the right side of the panel, note the values under the Class heading:

In the Service column, the names of WLM service classes are displayed. ZMGRDEFA is the default service class for z/OS WLM to use for work requests that are associated with a zEnterprise service class other than those listed on the left side of the panel. GPFASTHI is listed across from its corresponding zEnterprise service class, WebSales.
In the Report column, the name of a default report class is displayed. This name identifies the WLM report class that you can use to monitor performance data for work requests associated with all zEnterprise service classes.

When you use the ESC work qualifier for classification rules, you must observe the following restrictions:

The ESC work qualifier is valid only for the EWLM subsystem type.
A subrule must use the same work qualifier as its parent classification rule: ESC
A classification rule does not require a corresponding service class, and the EWLM subsystem type does not require a default service class. If processing of the classification rule does not result in the assignment of a valid WLM service class, the usual subsystem type specific WLM classification rules are applied to assign a WLM service class.
The name of each specified zEnterprise service class cannot be longer than 32 characters.
zEnterprise service class names are mixed case (fold qualifier name = N) and WLM uses case-sensitive names during the classification process.
WLM uses classification rules starting from the top of the list as shown on the modify subsystem panel, so WLM uses the first correlation it finds for a zEnterprise service class.
The selected WLM service class must have a response time goal; a velocity or discretionary goal is not supported.
The selected WLM service class cannot have a multi-period goal.
The selected WLM service class cannot belong to a resource group.