WebSphere Extended Deployment Compute Grid, Version 6.1
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Defining service policies for Compute Grid jobs

WebSphere Extended Deployment enhances service policy and workload management for the Compute Grid by providing a rule-based service policy methodology, a new completion time service policy goal type, and the ability to mix grid jobs and OLTP workloads in the same WebSphere application server. The features of the Operations Optimization component apply to the management of the Compute Grid environment when the two components, Compute Grid and Operations Optimization, are deployed together. You must have the Operations Optimization component installed to define service policies. See the Operations Optimization Information Center for more information on dynamic operations.

Refer to the WebSphere Extended Deployment Operations Optimization Information Center for more information on defining service policies.

Service policy classification in WebSphere Extended Deployment Compute Grid is controlled by a set of rules defined to the job scheduler. These rules can be composed of Boolean expressions and can include the following operand types:

See Job classification in Compute Grid for details on each of the previous operands.

Goals types

  • Discretionary goals indicate work that does not have significant value. As a result, work of this type can see a degradation in performance when resources are constrained.
  • Average response time goals are indicative of work with a higher priority than discretionary. The average response time goal is assigned a specific time goal on the following panels.
  • Percentile response time goals are another measure for work with a higher priority than discretionary. The percentile response goals are defined with specific criteria on the following panel. The percentile response time target is the percentage of requests whose response time is T or less that should be P or more; a target has particular values for T and P.
  • [Version 6.1.0.1 and later] Completion time goals specify the maximum amount of time (minutes) that is acceptable for a job to complete and still maintain the level of service that the service policy implies. Queue time goals are deprecated in Version 6.1. Completion time is queue time plus execution time of a grid job. Completion time combined with the importance associated with service policies ensure that important jobs are dispatched first. All jobs are dispatched immediately if there is capacity. This completion time goal type is used only when there are more jobs than what can be processed immediately. The attempt is to get the job completed by completion time, and not just get dispatched. The application placement controller (APC) assesses the historical date for a job and dispatches the job based on that data. For example, if completion time is set to 30 minutes, and from historical date the APC knows that the job takes 30 minutes to complete, then this job will be dispatched right away. The class of a job is important when predicting the performance characteristics of batch jobs. The APC design is such that the system assumes that a job in class A will have (broadly) the same performance characteristics as other jobs in class A.

Default classification rules and precedence

WebSphere Extended Deployment V6.1 provides two default classification rules:

  1. A rule that assigns any job of type Java 2 Platform Enterprise Edition (J2EE) to the transaction class defined by the named J2EE application's default IIOP work class.
  2. A rule that assigns any job to the default transaction class, DEFAULT_TC

Both default rules can be edited and deleted. The order of the rules can be modified, and user-defined classification can be added. The job scheduler evaluates the list of classification rules in order and assigns the transaction class specified by the first matching rule. Only one classification rule set per cell is supported in WebSphere Extended Deployment Version 6.1. A default configurable transaction class, named DEFAULT_TC by default, is associated with this set. If none of the classifications rules match a job, then the default transaction class is applied to that job. Graphical user interface (GUI) support for choosing a transaction class from a drop-down list while building a rule is only present in the presence of Operations Optimization package. In a Compute Grid only environment there is a text field where a transaction class name is specified.




Related information
Managing Compute Grid jobs and their environment
Concept topic    

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Last updated: Oct 30, 2009 6:22:31 PM EDT
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