CICSPlex SM time zone attribute usage

You make use of the three attributes that facilitate timing services when you specify CMAS definitions, CICSplex definitions, CICS® system definitions, and time period definitions.

CMAS

To ensure consistent timing services, CICSPlex® SM requires that the attribute settings within a CMAS accurately reflect the time in effect for the location in which that CMAS executes.

There are three uses for these attributes in a CMAS:

To coordinate time services throughout a CICSplex, CICSPlex SM bases all of its timing on GMT. When a CMAS is started, CICSPlex SM calculates how a standard hardware clock must be modified to achieve GMT. This is done in one of two ways, depending upon the setting of the z/OS® CVT data field CVTTZ:
- When the CVTTZ data field is non-zero, CICSPlex SM assumes that the hardware clock value is GMT, and does not modify it.
- When the CVTTZ data field is zero, CICSPlex SM uses the time zone, time zone adjustment, and daylight savings indicator in the CMAS to calculate the value needed to modify the hardware clock.
Note that the contents of the CVTTZ data field are based upon the SYS1.PARMLIB(CLOCKxx) member:
- If the CLOCKxx member indicates that the Sysplex Timer is in use, the CVTTZ data field is set based upon the contents of the Sysplex Timer.
- If the CLOCKxx member indicates that the Sysplex Timer is not in use, the CVTTZ data field is set based upon the contents of the CLOCKxx member TIMEZONE operand.
When an analysis definition or status definition is installed within an analysis point specification that is controlled by the CMAS, and the definition is scheduled for a timed install (because the definition is associated with a period definition), then the time zone, time zone adjustment and daylight savings indicator of the CMAS determine when the definition is installed, provided that the period definition indicates that the install time should be local time.
When a CICS system is defined to CICSPlex SM, the time zone, time zone adjustment and daylight savings indicator can be explicitly set, or they can be inherited from the CMAS to which the CICS system connects.

CICSplex

Because a CICSplex may encompass many different time zones, and to ensure consistency within the CICSplex, it is required that a single set of attributes be chosen to represent the CICSplex. It is not necessary that the attributes chosen match the attributes of the maintenance point CMAS of the CICSplex, or any other CMAS.

There is one use for the time zone attributes in a CICSplex:

When a CICSplex becomes active, and monitoring will be active, a monitor interval is determined based upon the setting in the CICSplex definition. This monitor interval is used to reset monitor data collected from CICS system. Because each CMAS in the CICSplex stores the monitor data for the CICS systems connected to it, in order for all monitor data within the CICSplex to be consistent the reset takes place at all CMASs at exactly the same real time, regardless of the locations of the CMASs. To compute the time for the reset, the time zone attributes of the CICSplex are used.

CICS system

Unlike the attribute requirements for a CMAS, the time zone attributes for a CICS system can be set to reflect a location different from that where the CICS system actually executes. For example, if the system executes in one time zone, but is primarily used by operators in another time zone, you may prefer to set the attributes to match the time zone of the operators, instead of matching the time zone where the system executes. CICSPlex SM supports either actual or logical attributes for CICS systems.

There are three uses for these attributes in a CICS system:

When a monitor definition is installed within a monitor specification within the CICS system, and the monitor definition is scheduled for a timed install (because the monitor definition is associated with a period definition), the time zone, time zone adjustment and daylight savings indicator of the CICS system are used to determine when to install the definition, provided that the period definition indicates that the install time should be local time.
When an analysis definition or status definition is installed within an analysis specification within the CICS system, and the analysis definition is scheduled for a timed install (because the definition is associated with a period definition), the time zone, time zone adjustment, and daylight savings indicator of the CICS system are used to determine when to install the definition, provided that the period definition indicates that the install time should be local time.
When a CICS system has System Availability Monitoring (SAM) active (the CICS system definition contains both a primary CMAS and an active period), the time zone, time zone adjustment, and daylight savings indicator of the CICS system are used to determine when the system should be active, provided that the period definition indicates that the time period should be local time.

Period definition

Period definitions are used by CICSPlex SM to schedule timed events. A period definition is defined as a starting time, an ending time, and time zone attributes. Period definitions use only two of the time zone attributes: the time zone and the time zone adjustment.

There are three uses of period definitions:

For System Availability Monitoring (SAM). This occurs when both a primary CMAS and a period definition are associated with a CICS system definition.
Note: If no Period definition name is specified in the Administration views > System availability monitoring administration views > CICS system definition detail view (CICSSYS in the end user interface), SAM is not activated for that CICS system.
For timed install of monitor definitions. This occurs when a period definition is associated with a monitor definition when the monitor definition is added to a monitor group, and the monitor group is installed into a CICS system.
For timed install of analysis definitions and status definitions. This occurs when a period definition is associated with an analysis definition or a status definition when the definition is added to an analysis group, and the analysis group is installed into a CICS system or an analysis point specification.

For a period definition, there are two differences from other uses of the time zone attributes:

Time zone A is accepted by a period definition. Use of time zone A indicates that the time associated with the period definition reflects the local time of the entity (CMAS or CICS system).
When a period definition is defined with a time zone of A, the time zone adjustment specified in the period definition is ignored.

When a period definition is for time zone A, all events controlled by that period definition become active at the same clock time, based upon the start time specified in the period definition, and the time zone, time zone adjustment, and daylight saving indicator within the entity (CMAS or CICS system). Similarly, events become inactive at the same clock time, based upon the end time specified in the period definition, and the time zone, time zone adjustment, and daylight saving indicator within the entity (CMAS or CICS system).

When a period definition is for a time zone other than time zone A, all events controlled by that period definition become active at exactly the same real time, regardless of the time zone in which the events are occurring. The activation time is based upon the period definition’s start time, time zone, and time zone adjustment. Similarly, events controlled by that period definition become inactive at the same real time, based upon the period definition’s ending time, time zone, and time zone adjustment. For both activation and deactivation, the time zone specified refers to the standard time for that time zone (LST), regardless of whether daylight saving time is in effect.