Assigning storage classes

With the exception of tape data sets, a data set is SMS-managed if it is assigned a storage class. You can assign storage classes either through the storage class ACS routine or by explicit specification. If you do not specify an explicit storage class when you store an object, the object is assigned the storage class that is defined in the collection to which the object belongs. The default storage class for an object collection is assigned by the ACS routine when the first object is stored in that collection. If the storage class ACS routine determines a storage class, it takes precedence over one that is explicitly specified by any of the following:

JCL DD statements
TSO/E ALLOCATE command
DFSMSdss COPY and RESTORE commands
Access method services ALLOCATE, DEFINE, and IMPORT commands
Dynamic allocation requests, such as with ISPF/PDF data set allocation panels
OSREQ STORE and CHANGE requests

ACS routines are required for Distributed FileManager/MVS-created data sets to ensure that they are SMS-managed. These data sets must be SMS-managed. If a remote application attempts to create a local data set in non-SMS-managed storage, Distributed FileManager/MVS refuses to honor the request because it only creates SMS-managed data sets. Distributed FileManager/MVS does, however, support the access of non-SMS-managed data sets.

The syntax for specifying a storage class on a JCL statement is

STORCLAS=storage-class-name

The syntax for specifying a storage class on a TSO/E command is:

STORCLAS(storage-class-name)

The syntax for specifying a storage class on an access method services command is:

STORCLAS(-)

The syntax for specifying a storage class on an OSREQ STORE or CHANGE macro is:

STORCLAS=storage-class-area or STORCLAS=(storage-class-area-pointer)

For information on determining storage classes with ACS routines, see Defining ACS routines.