HP OpenVMS System Manager's Manual, Volume 1:...

Managing the Queue Manager and Queue Database

Understanding the Queue Database

Understanding the Queue Manager  

Before you can perform any queue operation, you must start the queue manager and create the queue database. Starting the Queue Manager and Creating a Queue Database contains instructions for doing this.

OpenVMS Batch and Print Queuing System illustrates how the queue manager works to manage queue activity in an OpenVMS Cluster environment. 

Figure 1  OpenVMS Batch and Print Queuing System

When a user submits a batch or print job to a queue, the queue manager performs the following tasks:

1. Receives the user's queue request, including information about the type of job, the file name or names, the name of the queue, and any special options.
2. Stores and retrieves appropriate information from the queue database to print or execute the job.
3. Places the job in the appropriate queue to await its turn for processing:
   
   
   1. Print jobs are sent to an independent process, called a symbiont, for formatting and are then sent to the printer for printing.
   2. For batch jobs, the job controller creates a batch job process.

One or more queue manager processes control queuing for all processes on a node or in an OpenVMS Cluster environment. Jobs can be submitted from one node and executed on a queue running on another cluster node. User processes, symbionts, and job controllers on each node communicate directly with queue managers.

In addition, the job controller works with the queue manager to perform the following queue management tasks:

• Create and monitor batch, symbiont, and queue manager processes



• Restart the queue manager process on reboot



• Handle failover of the queue manager in an OpenVMS Cluster environment

Queue Manager Failover

By default, in an OpenVMS Cluster environment, the queue manager tries to fail over to another node if the node on which the queue manager is running leaves the cluster.

You can specify the order in which OpenVMS Cluster nodes claim the queue manager process; you can also limit the nodes that can run the queue manager. For more information, see Customizing Queue Manager Failover.

Multiple Queue Managers

To work around CPU, disk space, or memory limitations, you can use multiple queue managers to distribute the batch and print work load among nodes as well as to distribute the database files among disks.

For example, you might create separate queue managers for batch queues and print queues. Run the batch queue manager on one node and the print queue manager on a different node. You can also maintain queue and journal files on separate disks.

For information about creating additional queue managers, including reasons and restrictions for using multiple queue managers, see Using Multiple Queue Managers.

Understanding the Queue Database