Subsystems


A Subsystem is a process that is responsible for executing jobs in a Queue on the Enterprise Management Server. Jobs are first sent to a Queue with a priority. Then a Queue feeds the jobs into its assigned Subsystem as the jobs are executed and the space is made for the next job according to the Max Jobs setting for the Subsystem. There are 3 initial Subsystems that are preconfigured when the Server is first installed. These are:

  1. SBATCH - used for running general jobs. Typically a maximum number of jobs will be set to ensure that the server runs at optimum performance.
  2. SIMMED - used for high priority jobs that must be run the instant they enter the Server. This Subsystem has a maximum jobs of *NOMAX meaning that it will always accept and execute a job submitted to it without waiting.
  3. SSYSTEM - Used for running tasks that are part of the Enterprise Management Server. These tasks include the Subsystem Manager, Scheduler and Notification Manager. Generally you do not submit queued jobs to SSYSTEM.

New Subsystems may be created to meet your specific needs. You may wish to create a Subsystem that only allows one job to run at a time. You can then use this Subsystem to run jobs that should not be run together. The Subsystem manager will ensure that only 1 job is active in this Subsystem if the maximum number of jobs is set to 1. By creating the necessary Subsystems it is possible to optimize the load on your server and subsequently obtain the greatest performance.

Column definitions

Subsystem Column Headers

Job Headers

Controlling Subsystems

Creating a new Subsystem

To create a new Subsystem click once on any of the existing Subsystems. A popup menu will be displayed. Choose Create New... . The cursor will then be placed in an empty space of the display. Enter the desired name for the new Subsystem and press Enter. The new Subsystem will be created with the default settings.

Setting the maximum number of jobs

To set the maximum number of jobs that the Subsystem can run at any one time click once on the Subsystem. A popup menu will be displayed. Choose Set Maximum Jobs and choose a value from the right hand popup. *NOMAX indicates that this Subsystem does not have a maximum number of jobs. In this case jobs submitted to the job queue that feeds this Subsystem will be active immediately in this Subsystem. Generally SIMMED is set up for this purpose. Typically Enterprise Java Bean jobs will usually be run in a Subsystem that has *NOMAX for the maximum number of jobs.

Adjusting the Subsystem priority

To adjust the Subsystem priority click once on the Subsystem. A popup menu will be displayed. Choose Set Priority and choose the desired priority. 10 is the highest priority, 1 is the lowest. That is, Subsystems running at priority 10 will receive more system resources than those running at a lower priority. Adjusting the priority of a Subsystem affects the amount of resources that the Subsystem receives as well as the jobs running in that Subsystem. Typically if a Subsystem only runs low priority jobs it would be wise to lower its priority to 4 or even 3 to give more resources to jobs that are more important.

Removing a Subsystem

To remove a Subsystem click on the Subsystem. A popup menu will be displayed. Choose Delete from the popup and press OK when the confirmation dialog box appears. SIMMED, SBATCH and SSYSTEM may not be removed.

Holding and releasing a Subsystem

If you wish to pause a Subsystem, and therefore all the jobs running in it, click on the Subsystem. A popup menu will be displayed. Choose Hold. The Subsystem and its jobs will then be held. To release the Subsystem click on it again and choose Release from the popup menu. The Subsystem will again become active along with all the jobs that are currently running in it.

Adjusting the screen refresh interval

To adjust how often the Subsystem list is refreshed click on a Subsystem and choose Refresh Every from the popup menu. Then select the desired interval. The Subsystems screen will then automatically refresh at the new interval. The screen will only refresh if it is visible. If another tab in the menu system is selected refreshing will not occur until the Server Manager is reselected and the Subsystems tab is selected. The screen will also automatically refresh each time the Subsystems tab is selected. Note that refreshing the screen continuously can cause an unnecessary load on the server especially if the job log of a particular job is also being displayed. The default refresh rate is 60 seconds.

Starting systems jobs

If for some reason you find it necessary to kill either the JDPScheduler or JDPNotificationMgr jobs it is possible to restart them again by clicking on the SSYSTEM Subsystem and choosing Start from the popup menu. Then choose the job that you wish to start from the right popup menu.

Controlling Jobs in a Subsystem

Holding and releasing a job

To hold a job that is currently active click once on it. A popup menu will be displayed. Choose Hold from the menu. The job is now suspended. To release the job click on it and choose Release from the popup menu.

Killing a job

To kill a job that is currently executing click once on it. A popup menu will be displayed. Choose Kill from the menu. The job will be terminated and a job log will be produced if specified for this job when it was initiated. Note that there is no confirmation dialog when killing jobs.

Displaying the job log of an active job

To display the current job log of an active job click once on the job. A popup menu will be displayed. Choose Display Job Log from the menu. The job log will be displayed in the lower half of the screen. To refresh the log simply press the refresh button at the bottom of the screen. Note that the job log will also automatically refresh at the preset refresh interval. This can cause an unnecessary load on the server. If you do not require this you should hide the job log by pressing the Hide Job Log button at the bottom of the screen.

Adjusting the job priority

To adjust the job priority click once on the job. A popup menu will be displayed. Choose Set Priority and choose the desired priority. 10 is the highest priority, 1 is the lowest. That is, jobs running at priority 10 will receive more system resources than those running at a lower priority. A jobs' overall priority is dependant not only upon the priority of the job but also the priority of the Subsystem in which it is running.