Coupling facility structure properties
We can set attributes for coupling facility structures. Coupling facility structures are available only on z/OS®.
For each attribute, there is a brief description of when you might need to configure the attribute. The tables also give the equivalent MQSC parameter for the ALTER CFSTRUCT and DISPLAY CFSTRUCT commands. For more information about MQSC commands, see Script (MQSC) Commands in the IBM MQ online product documentation.
General page
This table lists the attributes that we can set on the General page of the Coupling facility structure properties dialog.
Attribute Meaning MQSC parameter Coupling facility name Read-only. We cannot change the name of the coupling facility structure after it has been created. CFSTRUCT Coupling facility description Type a meaningful description of the purpose of the coupling facility structure. See Strings in property dialogs. DESCR Level Read-only. The functional capability level for this coupling facility application structure. CFLEVEL Recovery Read-only. This attribute specifies whether coupling facility structure recovery is supported for the application structure. RECOVER Loss of coupling facility connectivity Specifies the action taken when the queue manager loses connectivity to the CF structures with. The three options are: This parameter is only valid from CFLEVEL(5) or later. Setting this attribute for a structure at a CFLEVEL earlier than 5 results in PCF reason code MQRCCF_PARM_CONFLICT being returned.
- As queue manager. The action taken is based on the setting of the queue manager CFCONLOS attribute.
- Tolerate. The queue manager tolerates a loss of connectivity to CF structures and does not terminate.
- Terminate. The queue manager terminates when connectivity to CF structures is lost.
CFCONLOS Automatic recovery Specifies the automatic recovery action when a queue manager detects that the structure has failed. Or when a queue manager loses connectivity to the structure and no systems in the SysPlex have connectivity to the Coupling Facility that the structure is allocated in. The value can be any of the following values: This parameter is valid only from CFLEVEL(5) or later. Setting this parameter for a structure at a CFLEVEL earlier than 5 results in PCF reason code MQRCCF_PARM_CONFLICT being returned.
- Yes. The structure and associated shared message data sets are automatically recovered.
- No. The structure is not automatically recovered.
RECAUTO Alteration date Read-only. The date on which the coupling facility structure's attributes were last altered. ALTDATE Alteration time Read-only. The time at which the coupling facility structure's attributes were last altered. ALTTIME Status Read-only. The current status of the coupling facility structure. STATUS
Message offload page
This table lists the properties that we can set on the Message offload page of the Coupling facility structure properties dialog.
Property Meaning MQSC parameter Offload If required, select where the message data for a shared queue is stored. This can be Db2®, SMDS (shared message data set) or None if no offload is required. OFFLOAD Offload rule 1 threshold (%) Edit this value to represent your initial threshold for the used capacity of the coupling facility structure. For example 70% would represent that the offload would be triggered when 70% of the coupling facility structure storage was used. OFFLD1TH Offload rule 1 size Edit this value to represent the size of messages selected to be offloaded when the capacity threshold specified in the Offload rule 1 is reached. All messages exceeding the size specified will be selected to be offloaded. For example 32k would indicate that all messages exceeding 32k would be offloaded. OFFLD1SZ Offload rule 2 threshold (%) Edit this value to represent your secondary threshold for the used capacity of the coupling facility structure. For example 80% would indicate that the offload would be triggered when 80% of the coupling facility structure storage was used. OFFLD2TH Offload rule 2 size Edit this value to represent the size of messages selected to be offloaded when the capacity threshold specified in the Offload rule 2 is reached. All messages exceeding the size specified will be selected to be offloaded. For example 4k would indicate that all messages exceeding 4k would be offloaded. OFFLD2SZ Offload rule 3 threshold (%) Edit this value to represent your final threshold for the used capacity of the coupling facility structure. For example 90% would represent that the offload would be triggered when 90% of the coupling facility structure storage was used. OFFLD3TH Offload rule 3 size Edit this value to represent the size of messages selected to be offloaded when the capacity threshold specified in the Offload rule 3 is reached. All messages exceeding the size specified will be selected to be offloaded. For example 0k would indicate that all remaining messages would be offloaded. OFFLD3SZ Generic data set name Edit this value to provide the generic data set name to be used for the group of shared message data sets associated with this structure. DSGROUP Logical block size Edit this value to provide the logical block size, which is the unit that shared message data set space is allocated to individual queues DSBLOCK Number of buffers Edit this value to provide the number of buffers to be allocated in each queue manager for accessing shared message data sets. DSBUFS Expand data set Edit this parameter to control whether the queue manager should expand a shared message data set when it becomes nearly full, and further blocks are required in the data set. EXPAND