XCF_CF_MEMORY_UTILIZATION
- Description:
- The check raises an exception when a coupling facility reaches
the memory utilization percentage threshold defined for the check.
Efficient and planned coupling facility memory utilization prevents
a CF from becoming over-full and thereby allows the CF to allocate
new structures, expand structures, sustain a viable failover environment
and participate in structure rebuild and reallocation processing when
needed. The memory utilization threshold percentage will be accepted
as a parameter to the check. Note that XCF, independent from this
check, will automatically contract structures to relieve coupling
facility resource constraints when a coupling facility as a whole
is at or above 90% memory utilization and coupling facility resources
are not being used productively by the structures.
This is a local check.
- Reason for check:
- The percentage of memory use in a coupling facility should not approach an amount high enough to keep it from allocating of new structures or expanding existing structures.
- z/OS® releases the check applies to:
- z/OS V1R12 and later.
- Parameters accepted:
- MAXUTILIZATION is a required parameter indicating the threshold
percentage that the Coupling Facility memory utilization should not
exceed. The number must be an integer in the range of 1 to 99. Specifying
a percent (%) sign is optional (e.g. MAXUTILIZATION(60%)).
It is possible that system-initiated alter processing for a structure may start and increase the memory utilization percentage for a coupling facility before the check executes or raises an exception. This check may issue an exception during reconfiguration actions or during maintenance windows when the percentage of memory use exceeds the specified check parameter.
- User override of IBM values:
The following sample shows the defaults for customizable
values for this check. Use this sample to make permanent check
customizations in an HZSPRMxx parmlib member used at
IBM Health Checker for z/OS startup. If you just want a one-time
only update to the check defaults, omit the first line (ADDREPLACE POLICY)
and use the UPDATE statement on a MODIFY hzsproc command.
Note that using non-POLICY UPDATEs in HZSPRMxx can
lead to unexpected results and is therefore not recommended.
ADDREPLACE POLICY[(policyname)] [STATEMENT(name)]
UPDATE
CHECK(IBMXCF,XCF_CF_MEMORY_UTILIZATION)
SEVERITY(MED) INTERVAL(001:00) DATE (20090707)
PARM(‘MAXUTILIZATION(60)’)
REASON('Your reason for making the update.')- Reference:
- For more information, see z/OS MVS Setting Up a Sysplex.
- Messages:
- This check issues the following exception messages:
- IXCH0456E
- SECLABEL recommended for MLS users:
- SYSLOW