DFSMS Hierarchy

The following flowchart reveals the logic flow used when CA Disk processes an SMS managed data set. It should assist you in understanding how the CA Disk SMS sysparms process an SMS managed data set.

The following illustration is an SMS Hierarchy Flow chart:

The storage group attributes are used only for the ARCHIVE, BACKUP and VBACKUP functions. The logic flowchart is based on a TRUE and FALSE condition with the TRUE condition being the first exception.

When an SMS managed data set is processed using management class or storage group attributes, the expiration date value in the DSNINDEX record is always set to 99365.

When an SMS managed data set is processed through DSCL bypassing management class or storage group attributes; the expiration date value in the DSNINDEX record is established in 1 of 3 ways:

Specifying RETPD on the DSCL command
Specifying EXPDT on the DSCL command
Supplying a retention period to sysparm RETRETPD

This is also true for SMS managed data sets with no assigned management class.

When a data set is processed using SMS management class, CA Disk only uses the management class attributes. By default, the expiration date for all SMS managed backup and archive DSNINDEX records is set to 1999.365, but this does not mean they will never expire. Their actual expiration occurs as follows:

For a backup DSNINDEX record — this type of record is deleted when other backups are made after the physical data set on DASD is modified, or after the data set is physically deleted from DASD and no archive copies exist. All of this is based upon the management class backup attributes.
For an archive DSNINDEX record — this type of record is kept until the expiration attributes in the management class are met. Therefore, the 1999.365 is used as a place holder. Expiration of the most current cataloged Archived copy is based on two management class fields:
- Expire days/date
- Expire after days non-usage

For more information about this deletion process, see SMS Information Within The Archives in the chapter "FILES Maintenance." When an SMS data set is processed using CA Disk commands, any management class attributes assigned to the data set are ignored for the execution.

Finally, the IXMAINT & EXPIRE functions honor Management Class attributes as described in the DFSMS Storage Administration Guide. If you are processing GDG data sets, the NOLIMIT values should be fully understood because the action taken depends on the actual definition of the GDG Sphere, especially while you're using the SCRATCH or NOSCRATCH parameters.