DEFINE STGCLASS (define storage class to page set mapping) on z/OS

Use the MQSC command DEFINE STGCLASS to define a storage class to page set mapping.

Using MQSC commands

For information on how you use MQSC commands, see Performing local administration tasks using MQSC commands.

You can issue this command from sources 2CR. For an explanation of the source symbols, see Sources from which you can issue MQSC commands on z/OS®.

Syntax diagram
Usage notes for DEFINE STGCLASS
Parameter descriptions for DEFINE STGCLASS

Synonym: DEF STC

Values shown above the main line in the railroad diagram are the defaults supplied with IBM® MQ, but your installation might have changed them. See Syntax diagrams.

DEFINE STGCLASS

Notes:

¹ Valid only on z/OS when the queue manager is a member of a queue sharing group.

Usage notes for DEFINE STGCLASS

The resultant values of XCFGNAME and XCFMNAME must either both be blank or both be nonblank.
You can change a storage class only if it is not being used by any queues. To determine whether any queues are using the storage class, you can use the following command:
```
DISPLAY QUEUE(*) STGCLASS(ABC) PSID(n)
```
where 'ABC' is the name of the storage class, and n is the identifier of the page set that the storage class is associated with.

This command gives a list of all queues that reference the storage class, and have an active association to page set n, and therefore identifies the queues that are actually preventing the change to the storage class. If you do not specify the PSID, you just get a list of queues that are potentially stopping the change.

See the DISPLAY QUEUE PSID command for more information about active association of a queue to a page set.

Parameter descriptions for DEFINE STGCLASS

(storage-class)

Name of the storage class.

This name is one to 8 characters. The first character is in the range A through Z; subsequent characters are A through Z or 0 through 9.

Note: Exceptionally, certain all numeric storage class names are allowed, but are reserved for the use of IBM service personnel.

The storage class must not be the same as any other storage class currently defined on this queue manager.

CMDSCOPE

This parameter specifies how the command runs when the queue manager is a member of a queue sharing group.

CMDSCOPE must be blank, or the local queue manager, if QSGDISP is set to GROUP.

' ': The command runs on the queue manager on which it was entered.
qmgr-name: The command runs on the queue manager you specify, providing the queue manager is active within the queue sharing group.
You can specify a queue manager name other than the queue manager on which it was entered, only if you are using a shared queue environment and if the command server is enabled.
*: The command runs on the local queue manager and is also passed to every active queue manager in the queue sharing group. The effect of * is the same as entering the command on every queue manager in the queue sharing group.

DESCR( description )

Plain-text comment. It provides descriptive information about the object when an operator issues the DISPLAY STGCLASS command.

It must contain only displayable characters. The maximum length is 64 characters. In a DBCS installation, it can contain DBCS characters (subject to a maximum length of 64 bytes).

Note: If characters are used that are not in the coded character set identifier (CCSID) for this queue manager, they might be translated incorrectly if the information is sent to another queue manager

LIKE( stgclass-name )

The name of an object of the same type, with parameters that are used to model this definition.

If this field is not completed, and you do not complete the parameter fields related to the command, the values are taken from the default definition for this object.

Not completing this parameter is equivalent to specifying:


LIKE(SYSTEMST)

This default storage class definition can be altered by your installation to the default values required.

The queue manager searches for an object with the name you specify and a disposition of QMGR or COPY. The disposition of the LIKE object is not copied to the object you are defining.

Note:

QSGDISP (GROUP) objects are not searched.
LIKE is ignored if QSGDISP(COPY) is specified.

PASSTKTA( application name )

The application name that is passed to RACF® when authenticating the PassTicket specified in the MQIIH header.

PSID( integer )

The page set identifier that this storage class is to be associated with.

Note: No check is made that the page set has been defined; an error is raised only when you try to put a message to a queue that specifies this storage class (MQRC_PAGESET_ERROR).

The string consists of two numeric characters, in the range 00 through 99. See DEFINE PSID (define page set and buffer pool) on z/OS.

QSGDISP

Specifies the disposition of the object in the group.

Table 1. Object dispositions for QSGDISP options
QSGDISP	DEFINE
COPY	The object is defined on the page set of the queue manager that executes the command. It uses the QSGDISP(GROUP) object of the same name as the LIKE object. For example, if you issue the following command, `DEFINE STGCLASS(storage_class_name) REPLACE QSGDISP(COPY)` the queue manager searches the shared configuration repository for an `STGCLASS` definition called `storage_class_name`. If a matching `STGCLASS` definition is found, the queue manager creates a local copy of this definition on the queue manager page set. For local queues, messages are stored on the page sets of each queue manager and are available only through that queue manager.
GROUP	The object definition resides in the shared configuration repository. QSGDISP(GROUP) is allowed only if the queue manager is in a queue sharing group. If the DEFINE for the QSGDISP(GROUP) object is successful, the `DEFINE STGCLASS(storage_class_name) REPLACE QSGDISP(COPY)` command is generated and sent to all active queue managers in the queue sharing group to make or refresh local copies on page set zero. The DEFINE for the group object takes effect regardless of whether the generated command with QSGDISP(COPY) fails.
PRIVATE	Not permitted.
QMGR	The object is defined on the page set of the queue manager that executes the command.

REPLACE and NOREPLACE

Whether the existing definition, and with the same disposition, is to be replaced with this one. Any object with a different disposition is not changed.

REPLACE: The definition replaces any existing definition of the same name. If a definition does not exist, one is created.
If you use the REPLACE option, all queues that use this storage class must be temporarily altered to use another storage class while the command is issued.
NOREPLACE: The definition does not replace any existing definition of the same name.

XCFGNAME( group name )

If you are using the IMS bridge, this name is the name of the XCF group to which the IMS system belongs. (This name is the group name specified in the IMS parameter list.)

This name is 1 - 8 characters. The first character is in the range A through Z; subsequent characters are A through Z or 0 - 9.

XCFMNAME( member name )

If you are using the IMS bridge, this name is the XCF member name of the IMS system within the XCF group specified in XCFGNAME. (This name is the member name specified in the IMS parameter list.)

This name is 1 - 16 characters. The first character is in the range A through Z; subsequent characters are A through Z or 0 - 9.