XCF_SFM_CFSTRHANGTIME

Description:

This check monitors the current setting of the CFSTRHANGTIME value in the sysplex failure management (SFM) policy to make sure it has not changed from the setting most desirable for your installation. It does this by comparing the SFM CFSTRHANGTIME value with the check parameter CFSTRHANGTIME value that you specify, issuing an exception message if the two are not consistent. The CFSTRHANGTIME SFM parameter specifies the amount of time you are willing to wait before the system takes automatic action to relieve hangs caused when a connector fails to respond to structure-related events in a timely manner.

Reason for check:

Installation should specify SFM policy parameter CFSTRHANGTIME so that the system automatically takes action to relieve hangs in CF structure-related processes caused by a connector's failure to respond to structure-related events in a timely manner. Note that the CFSTRHANGTIME SFM policy attribute applies to any system using SFM, whether or not SFM is in use throughout the sysplex.

The IBM® default value for CFSTRHANGTIME is 900 seconds (15 minutes). However, installations must ensure that the check parameters reflect an appropriate value. Consider CFSTRHANGTIME carefully to arrive at a value that reflects the needs, goals, and prior experiences for a given configuration. In general, it is desirable to select a fairly aggressive value to limit sympathy sickness when connectors fail to respond to events in a timely manner, but this must be balanced against the possibility of terminating connectors prematurely.

z/OS® releases the check applies to:

z/OS V1R12 and later.

Parameters accepted:

Yes. PARM('CFSTRHANGTIME(NO | seconds)'):

NO: Indicates that the system should not take automatic action to relieve a hang in a structure-related process.
seconds: Specifies the time interval, in seconds, that a coupling facility structure connector can remain unresponsive before the system takes action to relieve a hang in a structure-related process.
900 is the default value for this check parameter.

This check generates an exception if the check parameter you specify is not consistent with the existing SFM policy CFSTRANGTIME parameter. For instance, the check generates an exception if:

The SFM policy specifies or defaults to CFSTRHANGTIME(NO), but the check parameter specifies a value other than NO.
The SFM policy specifies a CFSTRHANGTIME decimal number of seconds, but the check parameter is either NO or a value less than the value specified in the SFM policy.

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(IBMXCF,XCF_SFM_CFSTRHANGTIME)
       SEVERITY(MED) INTERVAL(004:00) DATE('date_of_the_change')
       PARM('CFSTRHANGTIME(900)')                
       REASON('Your reason for making the update.')

Reference:

For more information, see z/OS MVS Setting Up a Sysplex.

Messages:

This check issues the following exception messages:

IXCH0531E

See the IXCH messages in z/OS MVS System Messages, Vol 10 (IXC-IZP).

SECLABEL recommended for MLS users:

SYSLOW