CA Dispatch Archive and Extract tasks - INTERNAL or EXTERNAL?

Document ID : KB000074459
Last Modified Date : 21/03/2018
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Introduction:
What is CA Technologies recommendation for running the CA Dispatch ARCHIVE and EXTRACT subtasks.
Question:
Should we run them INTERNALLY under the main CA Dispatch address space? Or, is it better to run them EXTERNALLY in their own address space?
Environment:
z/OS
Answer:
If you run these subtasks INTERNALLY, It basically means that CA Dispatch is "single threaded" in that, it can only be bouncing I/O to one subtask at a time. For example, if archive or extract is running internally and a tape mount request comes up, all other activity in Dispatch STOPS until that tape mount is satisfied. So, users and report processing functions could be affected.

When you run the EXTERNALLY, these subtasks run in their own address spaces and consequently, create very little overhead on the MAIN Dispatch region. User and report processing functions are not affected in the same manner as they would be if running these subtasks internally.

It is for the above reasons that CA recommends that archive and extract run EXTERNALLY.                                                                                                       
There is a very comprehensive discussion regarding the archive and extract subtasks, running them as internal or external, startup and shutdown commands, as well as CA's recommendation to run them externally in Chapter 2 of the CA Dispatch User Guide For the Report Administrators Manual. In here, you will find a section entitled STARTING AND ENDING THE SUBTASKS. Read through this entire section and you will get to a subsection entitled RUNNING SUBTASKS INTERNAL OR EXTERNAL. The answers to many of your questions can be found here.     
                                                                       
For information on specifically setting the ARCHIVE and EXTRACT tasks up to run as STC's see the HOW TO START EXTERNAL TASKS AS STARTED TASKS topic in the CA Dispatch Reference Guide towards the back, in the A: OPERATORS HANDBOOK section.
Additional Information: