Uses of filtering

You will make the best use of filtering by data set names if you use meaningful naming conventions. Your naming conventions should allow you to identify large groups of data sets that can be treated similarly. With such conventions, you can use data set name filtering to select large groups of data sets against which you can run DFSMSdss functions.

Suppose you are a storage administrator and you want to do a daily backup of all payroll data sets that have changed since they were last backed up. If the data sets you want to back up have some identifying qualifiers (for example, PAYROLL.FEDTAX), you can select them by coding:

//VRPAY     JOB  Accounting Information,MORGAN
//STEP1     EXEC PGM=ADRDSSU,REGION=4000K
//SYSPRINT  DD   SYSOUT=*
//DROUT     DD   DSN=PAYROLL.DAY1,DISP=(NEW,CATLG),UNIT=3480,LABEL=(1,SL)
//SYSIN     DD   *
     DUMP DATASET(INCLUDE(PAYROLL.FEDTAX.**)  -
                  BY((DSCHA,EQ,YES) (MGMTCLAS,EQ,DAILY)))  -
     OUTDD(DROUT)
/*

Filtering by data set characteristics also lets you process large groups of data sets. You can use BY criteria to:

Filter on the data-set-changed indicator to back-up only those data sets that have not been backed up since they were last updated.
Filter to select uncataloged data sets for deletion as a means of enforcing cataloging.
Filter to select data sets whose expiration date passed for deletion.
Filter on the last referenced date to archive or delete data sets that have not been referenced for a long period of time (for example, 18 months).
Filter on data set size to ensure that when you use the COMPRESS and RELEASE commands, you compress and release space only in data sets where the savings may be significant.
Filter on management class to perform space management (if in an SMS-managed environment).

It is possible to pass DFSMSdss filtering criteria in a data set by using the FILTERDD keyword. If you do this, the data set should have the following characteristics:

RECFM=F or FB
LRECL=80
BLKSIZE=80 for F (or a multiple of 80 for FB).