Management class defines the space and availability requirements for data sets. Its attributes control backup, migration, retention of data, and release of unused space. DFSMShsm uses information from the storage groups to determine what automatic management processes to run for the data sets on the volumes in the storage group. DFSMShsm manages data sets during the daily availability, primary and secondary space management, and interval migration processes, using the management classes assigned to your data sets from the active SMS configuration.

Assign all your system-managed permanent data sets to management classes, even if their management class attributes specify that no space or availability services are required for the data sets. If a management class is not assigned, DFSMShsm uses default management class attributes from your SMS configuration, or, if no default management class exists, it uses DFSMShsm defaults.

Tip: You can prevent DFSMShsm processing at the storage group level.

Data sets with varying management requirements coexist on the same volume. However, you might want to separate certain types of data sets with similar management requirements in their own storage group. An example is the production database data placed in a database storage group. You can use the image copy utilities of DB2® and IMS™ databases for backup and recovery. Because of the customized procedures required to back up and restore this data, you can separate it from data that uses DFSMShsm facilities.

Figure 1 through Figure 3 show the ISMF management class panel definitions required to define the STANDARD management class.

   Panel  Utilities  Scroll  Help
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                          MANAGEMENT CLASS DEFINE               Page 1 of 6
 Command ===>

 SCDS Name . . . . . . : YOUR.OWN.SCDS
 Management Class Name : STANDARD

 To DEFINE Management Class, Specify:

   Description ==>  This is the management class assigned
               ==>  to average data sets in the installation.

   Expiration Attributes
     Expire after Days Non-usage  . . NOLIMIT     (1 to 9999 or NOLIMIT)
     Expire after Date/Days . . . . . NOLIMIT     (0 to 9999, yyyy/mm/dd or
                                                  NOLIMIT)

   Retention Limit  . . . . . . . . . NOLIMIT     (0 to 9999 or NOLIMIT)



 Use ENTER to Perform Verification; Use DOWN Command to View next Panel;
 Use HELP Command for Help; Use END Command to Save and Exit; CANCEL to Exit.

The expiration and retention attributes for the STANDARD management class specify that no expiration date has been set in the management class. These data sets are never deleted by DFSMShsm unless they have explicit expiration dates.

   Panel  Utilities  Scroll  Help
 ------------------------------------------------------------------------------
                          MANAGEMENT CLASS DEFINE               Page 2 of 6
 Command ===>

 SCDS Name . . . . . . : YOUR.OWN.SCDS
 Management Class Name : STANDARD

 To DEFINE Management Class, Specify:

   Partial Release . . . . . . . . . Y           (Y, C, YI, CI or N)

   Migration Attributes
     Primary Days Non-usage  . . . . 15          (0 to 9999 or blank)
     Level 1 Days Non-usage  . . . . 30          (0 to 9999, NOLIMIT or blank)
     Command or Auto Migrate . . . . BOTH        (BOTH, COMMAND or NONE)


   GDG Management Attributes
     # GDG Elements on Primary . . .             (0 to 255 or blank)
     Rolled-off GDS Action . . . . .             (MIGRATE, EXPIRE or blank)

 Use ENTER to Perform Verification; Use UP/DOWN Command to View other Panels;
 Use HELP Command for Help; Use END Command to Save and Exit; CANCEL to Exit.

For single-volume data sets, DFSMShsm releases any unused space when you specify partial release. Also, if the data set is not referenced within 15 days, it moves to migration level 1, and, after 15 more days, moves to migration level 2.

For all VSAM data sets allocated in the extended format and accessed using the VSAM access method, you can use the Partial Release attribute of the management class to release allocated but unused space. The system releases the space either immediately during close processing, or during DFSMShsm space management cycle processing. This is similar to how the system processes non-VSAM data sets.

Panel  Utilities  Scroll  Help                                              
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                         MANAGEMENT CLASS DEFINE               Page 3 of 6    
Command ===>                                                                  
                                                                              
SCDS Name . . . . . . : YOUR.OWN.SCDS                                         
Management Class Name : STANDARD                                              
                                                                              
To DEFINE Management Class, Specify:                                          
  Backup Attributes                                                           
    Backup Frequency  . . . . . . . . 1        (0 to 9999 or blank)           
    Number of Backup Vers . . . . . . 2        (1 to 100 or blank)            
      (Data Set Exists)                                                       
    Number of Backup Vers . . . . . . 1        (0 to 100 or blank)            
      (Data Set Deleted)                                                      
    Retain days only Backup Ver . . . 60       (1 to 9999, NOLIMIT or blank)  
      (Data Set Deleted)                                                      
    Retain days extra Backup Vers . . 30       (1 to 9999, NOLIMIT or blank)  
    Admin or User command Backup  . . BOTH     (BOTH, ADMIN or NONE)          
    Auto Backup . . . . . . . . . . . Y        (Y or N)                       
    Backup Copy Technique . . . . . . S        (P, R, S, VP, VR, CP or CR)    
                                                                              
Use ENTER to Perform Verification; Use UP/DOWN Command to View other Panels;  
Use HELP Command for Help; Use END Command to Save and Exit; Cancel to Exit. 

DFSMShsm backs up the data set daily if the data set has been changed. The last two versions of the data set are retained as long as the data set exists on primary storage or migration level 1. If the data set is deleted, only one backup copy is retained. DFSMShsm does not use the high-availability backup technique, concurrent copy, for this data set.