Steps for defining the CDS and journal backup environment

The following is a sequence of steps for defining a CDS backup environment:

Add the SETSYS CDSVERSIONBACKUP command to the ARCCMDxx PARMLIB member.
Prevent the control data sets and the journal from being backed up as part of user data set backup. Control data sets and the journal are backed up separately as specified by the SETSYS CDSVERSIONBACKUP command.
If the control data sets and journal are SMS-managed:
- Place them on volumes that are defined in a storage group with
  AUTO BACKUP ===> NO
  
  or
- Associate them with a management class whose attributes are
  AUTO BACKUP ===> N
If the control data sets and the journal are non-SMS-managed, issue the ALTERDS command to prevent them from being backed up outside of CDSVERSIONBACKUP.
Prevent the control data sets and journal from migrating. Allowing the control data sets and the journal to migrate is inadvisable because you might not be able to recover should any of the control data sets be damaged.
If the control data sets and journal are SMS-managed:
- Place them on volumes that are defined in a storage group with
  AUTO MIGRATE ===> NO
  
  or
- Associate them with a management class whose attributes are COMMAND OR AUTO MIGRATE ===> NONE
If the control data sets and journal are non-SMS-managed, issue the SETMIG command to prevent them from migrating.
Determine whether your control data sets are backed up using concurrent copy. If you want your control data sets to be backed up using concurrent copy:
- Ensure that they are associated with a management class BACKUP COPY TECHNIQUE attribute of REQUIRED(R), PREFERRED (P), VIRTUALREQUIRED (VR), VIRTUALPREFERRED (VP), CACHEREQUIRED (CR), or CACHEPREFERRED (CP).
- Ensure that they are on a DASD volume with a concurrent-copy capable 3990 controller.
- Ensure that you specify DATAMOVER(DSS).

Determine whether the data mover for the control data sets is DFSMShsm or DFSMSdss. DFSMSdss is recommended as the data mover, because DFSMSdss validates the control data sets during BACKUP and supports concurrent copy.

If you specify . . .	Then . . .
SETSYS CDSVERSIONBACKUP (DATAMOVER(DSS) )	DFSMShsm invokes DFSMSdss to perform a logical dump of the control data sets and uses sequential I/O to back up the journal. DFSMSdss validates the control data sets while backing them up and uses concurrent copy if it was specified in the management class.
SETSYS CDSVERSIONBACKUP (DATAMOVER(HSM) )	DFSMShsm exports the control data sets and backs up the journal with sequential I/0. The control data sets are not validated during backup.

Choose the number of backup versions you want to keep for the control data sets. The number of backup versions that DFSMShsm keeps is determined by the number you specify on the BACKUPCOPIES subparameter of the SETSYS CDSVERSIONBACKUP command.
Note: Whenever DFSMShsm actively accesses the control data sets in RLS mode, DFSMSdss must be specified as the datamover for the CDS backup. If data is directed to tape, the PARALLEL parameter must also be specified. If either condition is not met during auto CDS version backup, these values override existing values and message ARC0793I is issued. If either of these conditions is not met when BACKVOL CDS is issued, the command fails.

Choose the device category (DASD or tape) on which you want DFSMShsm to back up your control data sets and journal. Parallel is faster than serial and is required in order to use concurrent copy.

If you specify . . .	Then . . .
SETSYS CDSVERSIONBACKUP (BACKUPDEVICECATEGORY (DASD) )	DFSMShsm always backs up the control data sets in parallel to DASD devices.

If you are backing up the control data sets and the journal to DASD, you must preallocate the backup version data sets. You can preallocate the DFSMShsm CDS and journal data set by running the starter set job ALLOCBK1 before starting DFSMShsm.

If you specify . . .	Then . . .
SETSYS CDSVERSIONBACKUP (BACKUPDEVICECATEGORY (TAPE) )	DFSMShsm backs up the control data sets to tape.

Whether tape CDS backups are in parallel is determined by the data mover you specify and the optional PARALLEL|NOPARALLEL option for DFSMShsm control data set backup.

If you specify . . .	Then . . .
SETSYS CDSVERSIONBACKUP (DATAMOVER(DSS) )	DFSMSdss backs up the control data sets to tape in parallel. Concurrent copy can be used.
SETSYS CDSVERSIONBACKUP (DATAMOVER(HSM) )	DFSMShsm backs up the control data sets serially. Concurrent copy is not available, and the control data sets are not validated during backup.
SETSYS CDSVERSIONBACKUP (DATAMOVER(HSM) PARALLEL )	DFSMShsm backs up the control data sets to tape in parallel. Concurrent copy is not available and the control data sets are not validated during backup. For more information about the PARALLEL\|NOPARALLEL tape option, refer to z/OS DFSMShsm Storage Administration.

If you are backing up the control data sets and the journal to tape, DFSMShsm dynamically allocates scratch tape volumes so you need not preallocate backup version data sets.

If you are backing up control data sets to DASD, you must catalog the CDS version backup data sets on all systems that are eligible for primary host promotion.

Determine the names for the backup data sets.
You specify the names that are assigned to the backup version data sets when you specify the MCDSBACKUPDSN, BCDSBACKUPDSN, OCDSBACKUPDSN, and the JRNLBACKUPDSN subparameters of the SETSYS CDSVERSIONBACKUP command. The backup version data set names can be up to 35 characters (including periods) and cannot end in a period.

Figure 1 is an example of the SETSYS CDSVERSIONBACKUP command and its subparameters, as it would appear in PARMLIB member ARCCMDxx.

Figure 1. Example CDSVERSIONBACKUP Command

/***********************************************************************/
/* SAMPLE SETSYS CDSVERSIONBACKUP COMMAND AND SUBPARAMETERS THAT       */
/* DEFINE A CDS BACKUP ENVIRONMENT WHERE DSS BACKS UP FOUR COPIES OF   */
/* THE CDSS IN PARALLEL TO DASD.                                       */
/***********************************************************************/
/*
SETSYS CDSVERSIONBACKUP(DATAMOVER(DSS) -
   BACKUPCOPIES(4) -
   BACKUPDEVICECATEGORY(DASD) -
   MCDSBACKUPDSN(BHSM.MCDS.BACKUP) -
   BCDSBACKUPDSN(BHSM.BCDS.BACKUP) -
   OCDSBACKUPDSN(BHSM.OCDS.BACKUP) -
   JRNLBACKUPDSN(BHSM.JRNL.BACKUP))
/*