Workload Manager: Difference between revisions

Revision as of 15:37, 26 June 2008

Revision as of 19:08, 30 June 2008

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On a mainframe computer many different applications execute at the same time. The expectations for executing work are consistent execution times and predictable access to databases. On [[z/OS]] the Workload Manager (WLM) component fulfills these needs by controlling work's access to system resources based on external specifications by the system administrator.

The system administrator '''classifies''' work to '''service classes'''. The classification mechanism uses work attributes like transaction names, user identifications or program names which are known specific applications are known to use. In addition the system administrator defines '''goals''' and '''importance levels''' for the service classes representing the application work. The goals define performance expectations for the work. Goals can be expressed as '''response times''', a relative speed (termed '''velocity''') or as '''discretionary''' if no specific requirement exists. The response time describes the duration for the work requests after they entered the system and until the application signals to WLM that the execution is completed. WLM is now interested to assure that the average response time of a set of work requests ends in the expected time or that a percentage of work requests fulfill the expectations of the end user.

The definition of a response time also requires that the applications communicate with WLM. If this is not possible a relative speed measure – named execution velocity - is used to describe the end user expectation to the system.