VSAMRLS_CFLS_FALSE_CONTENTION

Description:

The check looks for false contention on your system caused by a lock structure that is not big enough.

Reason for check:

If the lock structure size is too small, the system could experience excessive false contention, resulting in performance degradation. The acceptable false contention threshold is 5%. If the system experiences performance degradation, the lock structure size should be increased.

z/OS® releases the check applies to:

z/OS V1R9 and up.

Parameters accepted:

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. End of change

ADDREPLACE POLICY[(policyname)] [STATEMENT(name)]
UPDATE
CHECK(IBMVSAMRLS,VSAMRLS_CFLS_FALSE_CONTENTION)
SEVERITY(MED) INTERVAL(01:00) DATE('date_of_the_change')
PARMS('THRESHOLD(5000)')
REASON('Your reason for making the update.')

Debug support:

Verbose support:

Parameters accepted:

Yes:

PARMS('THRESHOLD(threshold)'): Specify an integer for the acceptable false contention threshold you want the check to use. This THRESHOLD value is specified in thousandths of a percent. The default value is PARM('THRESHOLD(5000)') which sets the false contention rate at which the health check issues an error to 5%.

Reference:

For more information, see the section on "Defining the CF Lock Structure" in z/OS DFSMSdfp Storage Administration.

Messages:

This check issues the following exception messages:

IGWRH0131E

See the IGWRH messages in z/OS MVS System Messages, Vol 9 (IGF-IWM).

SECLABEL recommended for MLS users:

SYSLOW