ZOSMIGV2R1_ZFS_VERIFY_CACHESIZE

Description:

Determines if the system is running with the default settings for IOEFSPRM configuration options meta_cache_size, metaback_cache_size and user_cache_size.

For user cache size, check if the current size is less than the z/OS® V2R1 default user cache size. For metadata cache size and metadata backing cache size, check if the sum of the two caches is less than the sum of the z/OS V2R1 defaults.

Reason for check:

Running with a very small cache size could affect zFS performance. This check issues an exception message if either or both of the conditions are true:

The sum of the current metadata cache size and metadata backing cache size is less than the sum of the V2R1 default metadata cache size and metadata backing cache size.
The current user cache size is less than the z/OS V2R1 default user cache size.

z/OS releases the check applies to:

z/OS V1R12 and z/OS V1R13.

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(IBMZFS,ZOSMIGV2R1_ZFS_VERIFY_CACHESIZE)  
SEVERITY(LOW)
INTERVAL(ONETIME)
PARM('META_CACHE=v2r1_size1,METABACK_CACHE=v2r1_size2,USER_CACHE=v2r1_size3’)
DATE('date_of_the_change')
REASON('Your reason for making the update.')

Note: The cache sizes (v2r1_size1, v2r1_size2 and v2r1_size3) are the internally calculated defaults as of z/OS V2R1 and later, based on the current configuration option settings and the amount of real storage during zFS initialization.

Debug support:

Verbose support:

Parameters accepted:

Specifying one or more keywords of meta_cache, metaback_cache and user_cache are acceptable. Each keyword defines a decimal number to be compared with the current cache size. The decimal number is limited to a length of 10 characters and a maximum value of 2147483647 (2G-1). A K, M or G can be appended to the number to mean kilobytes, megabytes or gigabytes, respectively.

The valid range for meta_cache is 1 M through 1024 M.
The valid range for metaback_cache is 1 M through 2097144 K
The valid range for user_cache is 10 M to 64 G.

For example:

PARM('USER_CACHE=1G')            /*  To override user_cache_size default */
PARM('META_CACHE=200000000,USER_CACHE=100000K')
PARM('META_CACHE=50M, METABACK_CACHE=32M,USER_CACHE=100M')

The default sizes are the internally-calculated cache sizes beginning in z/OS V2R1 based on the current configuration option settings and the real storage usage during zFS initialization.

Reference:

See the performance and tuning section in z/OS Distributed File Service zFS Administration to determine if the current setting would affect zFS performance.

See IOEFSPRM or zfsadm config in z/OS Distributed File Service zFS Administration to set or dynamically change the cache setting.

Messages:

This check issues the following exception message:

IOEZH0032E
IOEZH0033E

See z/OS Distributed File Service Messages and Codes.

SECLABEL recommended for multilevel security users:

SYSLOW - see z/OS Planning for Multilevel Security and the Common Criteria for information about using security labels.