How Job Management Manager Works › Job Management Manager in an OpenVMS Cluster › Balancing Job Loads Among Nodes in an OpenVMS Cluster

Balancing Job Loads Among Nodes in an OpenVMS Cluster

Job Management Manager provides the opportunity to use dynamic load balancing in an OpenVMS Cluster environment, and runs jobs on the computer that has the lowest current system activity. Your system manager can enable or disable this activity.

Load balancing is enabled by default for all systems in an OpenVMS cluster. To enable load balancing, use the SCHEDULE SET LOAD_BALANCE command. When you enable this feature, Job Management Manager scans all computers in the cluster that are currently running the manager and selects the least loaded of these nodes. The manager assigns the job to run on that node. You can also restrict a job to run on a subset of nodes in a cluster using Load Balance Groups. If you assign a Load Balance Group to a job, the job runs on the least loaded of the nodes in the Load Balance Group. All jobs are load balanced unless you turn off load balancing or a job is restricted to a particular node.

To verify if load balancing is currently enabled, use the SCHEDULE SHOW LOAD_BALANCE command.

For a description of how load balancing works, see the chapter "Getting Started with Job Management Manager."

The manager uses a currently least-loaded node approach to determine which node to run a job on. For more information about the algorithm the manager uses, see the chapter "Getting Started with Job Management Manager." If you must customize further, you can invoke a command procedure to use a different method to assign jobs to nodes in a cluster. For more information about how to specify your own load balancing algorithm, see the appendix "Customizing Load Balancing."