WebSphere Extended Deployment, Version 6.0.x
             Operating Systems: AIX, HP-UX, Linux, Solaris, Windows, z/OS


Configuring speed factors in multiple tier configurations

Use this task to compute and configure speed factors for your multiple tier configuration.

Before you begin

You must have WebSphere Extended Deployment installed and applications installed that are operational under a workload.

About this task

A speed factor exists for every combination of transaction class, target web module, and processing tier. The speed factor describes how heavily a request of the given transaction class, throughout the life in the given target module, loads the processing tier. You can define speed factors at varying levels of granularity. Speed factors can be defined in a broader scope. The ARFM uses speed factors at the level of service class, target deployment target, and processing tier. You can define speed factors at a variety of levels for any processing tier that is not a target tier or is not the one and only processing tier in the target module.

In a configuration that has multiple tiers, the work profiler automatically computes speed factors for the target tier. The target tier communicates directly with the on demand router (ODR). For any tiers that are deeper than the target tier, you must define speed factors. If your deployment target contains both an target tier and a non-target tier, you must configure the speed factors for both of the tiers because the work profiler cannot automatically compute speed factors in that situation. You can compute the speed factor by dividing average CPU utilization by the average number of executing requests. This task describes how to find these values and configure the speed factor for your multiple tier configuration.

Procedure

  1. Generate traffic for a transaction class and module pair. You can generate traffic by using an application client or a stress tool.
  2. Monitor CPU utilization in your configuration. Determine an average CPU utilization. You need the CPU utilization of all the machines that are involved in serving your traffic, and all machines that have performance interactions with them to be at the configured limit that is defined with the Maximum CPU utilization property on the Operational policies > Autonomic managers > Autonomic Request Flow Manager panel. Disable all the autonomic managers so that you can ensure the system does not make changes while you take the CPU utilization measurement:
    • The application placement controller: Disable the application placement controller by putting it in manual mode. Click Operational policies > Autonomic managers > Application placement controller. Click the Enable check box so that it is not checked to disable the application placement controller.
    • The autonomic request flow manager: You can use magic N mode if you are using only one flow, for example, an ODR, deployment target, and service class combination; otherwise, you might need to put the autonomic request flow manager in manual mode.
    • Dynamic workload management: Disable dynamic workload management for each dynamic cluster. Click Servers > Dynamic clusters > dynamic_cluster_name > Dynamic WLM. Click Dynamic WLM check box so that it is not checked to disable dynamic workload management.
    If you disable the autonomic managers, you can add CPU load through background tasks. Use an external monitoring tool for your hardware.
  3. Using the runtime charting in the administrative console, monitor the number of running requests. Click Runtime Operations > Runtime Topology in the administrative console. You can view the number of concurrent requests.
  4. Compute the speed factor for the deployment target. Using the following equation to calculate the speed factor:
    speed factor = (normalized CPU speed) * (CPU utilization) / 
    	(number of concurrent requests, measured at entry and exit of the target tier)
  5. Configure the speed factor in the administrative console. You set the custom property on the deployment target, for example, a cluster of servers or a standalone application server. For more information about the overrides that you can create with the speedFactorOverrideSpec custom property, see Autonomic request flow manager advanced custom properties .
    1. Define a case for each tier in the deployment target. Each case is separated by a comma. Each case contains a pattern that is set to a value that is equal to the speed factor that you calculated. The pattern defines the set of service classes, transaction classes, applications, or modules that you can override for the particular tier. The pattern is :
      service-class:transaction-class:application:module:[tier, optional]=value
      You can specify a wild card for any of the service class, transaction class, application, or module by entering a * symbol. Each pattern can include at most one application, at most one module, at most one service class, and at most one transaction class. The tier is optional, and represents the deployment target name and relative tier name. Set the value to a speed factor override number or to none to define no override. Following is an example of a speed factor override value for a two tier configuration:
      *:*:*:*=none,*:*:*:*:../DbCel/CICS=0.7
      For the first tier, there are no overrides. There is an override of 0.7 for the tier named CICS+1 that is in the cell named DbCel.
    2. Create the custom property in the administrative console. In the deployment target, click Custom properties > New. The name of the custom property is speedFactorOverrideSpec, and the value of the custom property is the string that you composed in the previous step.
    3. Save your configuration.

Results

Speed factors are configured to override the speed factor values that are created by the work profiler and support performance management of more than one tier.

What to do next

Repeat these steps for each transaction class module and non-target tier node pair. You also must configure the node speed for each external node. See Configuring node computing power for more information.



Related concepts
Multiple tiers of processing
Related tasks
Configuring the autonomic request flow manager
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Last updated: Nov 30, 2007 3:58:31 PM EST
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