VSAMRLS_CFCACHE_MINIMUM

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 shows the default keywords for the check, which you can override on either a POLICY statement in the HZSPRMxx parmlib member or on a MODIFY command. This statement may be copied and modified to override the check defaults:

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