VSAMRLS_CFCACHE_MINIMUM_SIZE

Description:

This check makes sure that all CF caches are above the IBM® recommended minimum size. This check identifies CF caches that are below the IBM recommended minimum value for the sysplex.

Reason for check:

The minimum CF cache size should be at least 10% of CF cache optimal size. A CF cache structure must be at least large enough to hold all of the MVS™ information required to describe a structure of maximum size. CF cache structures must be defined to MVS and also in the SMS base configuration. CF cache structures provide a level of storage hierarchy between local memory and DASD cache. They are also used as a system buffer pool for VSAM RLS data when that data is modified on other systems. Each CF cache structure is contained in a single CF. You might have multiple CFs and multiple CF cache structures. Performance should improve when the CF cache is larger than the sum of the local VSAM LRS buffer pool sizes. When the CF cache is smaller, performance depends upon the dynamics of the data references among the systems involved.

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_CFCACHE_MINIMUM_SIZE)
SEVERITY(MED) INTERVAL(24:00) DATE('date_of_the_change')
REASON('Your reason for making the update.')

Debug support:

Verbose support:

Reference:

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

Messages:

This check issues the following exception messages:

None

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

SECLABEL recommended for MLS users:

SYSLOW