USS_KERNEL_STACKS_THRESHOLD

Description:

This check monitors the current usage of z/OS® UNIX kernel stacks cell pool cells against a suggested threshold. Start of change

The check gets automatically DISABLED if KERNELSTACKS(ABOVE) is active. End of change

Reason for check:

If the number of kernel stack cell pool cells in use reaches the system maximum, additional cells cannot be allocated and system calls that use the kernel address space are disallowed. By monitoring stack cell usage installations might be able to prevent impacts to critical workloads by quiescing noncritical workloads before the supply of stack cells is exhausted.

z/OS releases the check applies to:

z/OS V2R1 and later.

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(IBMUSS,USS_KERNEL_STACKS_THRESHOLD)
INTERVAL(00:02)
SEVERITY(HIGH)
PARM('STACKS(85%)’)
DATE('20131005')

Debug support:

Verbose support:

Parameters accepted:

STACKS(n%) where n is an integer, 0-100, indicating the threshold percent for utilization of kernel stack cell pool cells.
Default: STACKS(85%)

Reference:

See:

z/OS MVS Initialization and Tuning Reference.

Messages:

This check issues the following exception messages:

BPXH071E

See the BPXH messages in z/OS MVS System Messages, Vol 3 (ASB-BPX).

SECLABEL recommended for multilevel security users:

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