CQS structure full monitoring

The z/OS® structure full monitoring capability can be used for queue structures and resource structures to warn you when a structure is approaching full and to prevent a full structure.

If structure full monitoring is enabled, z/OS monitors structure usage. When the number of entries or elements in use reaches the structure full threshold, z/OS issues a highlighted IXC585E message to warn the system programmer that a structure full condition is imminent. If automatic altering is enabled, z/OS automatically initiates a structure alter to increase the structure size or change the element-to-entry ratio.

Structure full monitoring is automatically enabled with a default threshold of 80%. Define a different threshold with the CFRM policy FULLTHRESHOLD parameter. Define the CFRM policy with FULLTHRESHOLD(0) to disable structure full monitoring. When the structure usage goes below the threshold, z/OS issues an IXC586I message.

The following command displays the structure full threshold that is in effect:

D XCF,STRUCTURE,STRNAME=strname

In the following example, the command D XCF,STRUCTURE,STRNAME=IMSRSRC01 is issued and the structure full threshold is 80%.

STRNAME: IMSRSRC01
  STATUS: NOT ALLOCATED
    POLICY SIZE      : 4096 K
    POLICY INITSIZE  : N/A
    FULLTHRESHOLD    : 80
    REBUILD PERCENT  : N/A
    DUPLEX           : DISABLED
    PREFERENCE LIST  : LF03
    ENFORCEORDER     : NO
    EXCLUSION LIST IS EMPTY

The following example shows the IXC585E message, indicating the structure is full because all of the entries are in use:

*IXC585E STRUCTURE IMSRSRC01 IN COUPLING FACILITY LF03, 725
 PHYSICAL STRUCTURE VERSION B4704775 92D95302,
 IS AT OR ABOVE STRUCTURE FULL MONITORING THRESHOLD OF 80%.
 ENTRIES:  IN USE:     4874 TOTAL:     4874, 100% FULL
 ELEMENTS: IN USE:       19 TOTAL:     4872,   0% FULL

The following example shows the IXC586I message:

IXC586I STRUCTURE IMSRSRC01 IN COUPLING FACILITY LF03, 772
PHYSICAL STRUCTURE VERSION B4704775 92D95302,
IS NOW BELOW STRUCTURE FULL MONITORING THRESHOLD.

Related reading: For more details on structure full monitoring and the FULLTHRESHOLD and ALLOWAUTOALT keywords in the CFRM policy, see z/OS MVS Setting Up a Sysplex.