Configuring Datacom MUF for XCF use
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Configuring Datacom MUF for XCF use


Article ID: 38170


Updated On:


Datacom/DB Datacom Datacom/AD


In order to access a Datacom Multi-User Facility (called MUF) from an LPAR in the Sysplex other than where the MUF is running, it is necessary to define a number of parameters to the MUF to support XCF (IBM Cross-system Coupling Facility) processing.

This document describes what is needed.



This applies to z/OS systems.



Here are a few things that you need to do to set up your MUF in support of both local and remote (XCF) processing:

  1. In your DBSIDPR assemble, you need to have CONNECT_ALLOW_PRIORITY=(LOCAL,XCF) to run from multiple LPARs.
  2. In the same DBSIDPR, you need to ensure you have a unique name for the MUF in TARGET_MUF_LIST=(), and that you are using a different TOGROUP from any other MUF. The unique MUF name is very important to keep your data integrity. When you make these changes, reassemble DBSIDPR. Note, too, that the MUF name must be different from the TOGROUP name.
  3. In your MUF startup options (CUSMAC member AXDATIN1 (Datacom/AD) or DBDATIN2 (Datacom/DB) ), ensure that the MUF option has an asterisk (*) in the first parameter.
  4. In the MUF options, be sure that XCF_FROM is uncommented and that the XCF group name has the same value as the TOGROUP from DBSIDPR.
  5. In the MUF options, be sure the TASKS option has an appropriate value in the 5th parameter (XCF value) to support the number of tasks you will be running on remote LPARs for your application. Many clients will set this to at least 50-80 percent of the total TASKS value.
  6. To utilize XCF processing, be sure your CAAXLOAD (Datacom/AD) or CABDLOAD (Datacom/DB) and your CUSLIB files are APF authorized on all LPARs where your tasks are running, and that you have loaded the Datacom PC Call module DBPCCPR with CAS9/CAIRIM on each of those LPARs. 

In summary, you need these in the DBSIDPR assembly

  • TOGROUP=<<1-8 character unique group name that you create, different from TARGET_MUF_LIST>>
  • TARGET_MUF_LIST=<<1-7 character unique MUF/CXX name that you create>>

*  Note that the MUF name must be different from the TOGROUP name and in the case of a Shadow MUF, both MUFs have the same 1-7 root name plus a one-character suffix (preferably A and B, or something like that).

You need these MUF startup options 

  • XCF_FROM  *,*,GROUPNAME,YES  <<groupname matches TOGROUP above>>
  • MUF       *,99,NO            <<first value should be *>>
  • TASKS     250,32K,0,0,100    << 5th value must be greater than 0>>

These points will cover the greatest majority of causes for applications on remote LPARs to not connect to a MUF.

Additional Information

As always, please contact Broadcom support for Datacom if you have further questions.