SMS Setup › SMS Definitions › DFSMS Data Class

DFSMS Data Class

CA Vtape requires that a data class with the following characteristics be defined:

Volume Count . . . . . . .: 2 
Data Set Name Type . . . .: EXTENDED 
  If Extended  . . . . . .: PREFERRED 
  Extended Addressability : NO 
  Record Access Bias . . .: USER 
Space Constraint Relief  .: YES 
  Reduce Space Up To (%) .: 50 
  Dynamic Volume Count . .: 2 

Note: A Record Organization (Recorg) of LS for Linear Data Set is not coded because this data class will be used for both VSAM and non-VSAM data set allocations. CA Vtape supplies the appropriate RECORG in its allocation requests.

The following explains each characteristic:

Volume Count

Reserves space in each catalog entry for the number of volumes entered. 2 is recommended to reserve some space in the catalog entry for multiple volume allocations.

Data Set Name Type

Extended ensures that the Data Sets are allocated in extended format. This is required for partial space release.

Extended Addressability

Allows a data set to exceed 4 GBs in size.

Record Access Bias

Allows CA Vtape to control record buffering.

Space Constraint Relief and Reduce Space Up To (%)

These parameters allow DFSMS to modify the space allocation requested by CA Vtape when the storage group becomes constrained for space.

Dynamic Volume Count

Allows a data set to be spanned to this number of DASD volumes if they are available in the storage group.

The other data class characteristics can be left at their default value or blank.