VERSIONS: Specifying the maximum number of backup versions to keep for any data set

Explanation: VERSIONS(limit) is an optional parameter specifying the maximum number of backup versions DFSMShsm keeps for any one data set. The maximum number of backup versions is limited to either 29 versions or 100 versions based on the BCDS record length. The following values are the valid maximum allowable number of backup versions for different BCDS record lengths:
  • Record length of 2040 to 6543 — 29 versions maximum
  • Record length of 6544 or more — 100 versions maximum

For limit, substitute a decimal number from 0 to 100. A zero (0) specifies that DFSMShsm does not create backup versions for any non-SMS-managed data set unless you specify the ALTERDS VERSIONS command.

SMS relationship: Parameter does not appply to SMS-managed DASD volumes or data sets.

SETSYS default: If you specify a value larger than the valid maximum allowable for that BCDS record length, the maximum value for that record length will be used. For example, if you specify SETSYS VERSIONS(50) and you have a BCDS record length of 2040 to 6543, the maximum allowable number of backup versions for this record length, which is 29, will be used.

DFSMShsm default: If you do not specify this parameter on any SETSYS command, the DFSMShsm default for limit is 2.
Note:
  1. The SETSYS VERSIONS parameter is used to specify the number of backup versions for all your non-SMS-managed data sets. An authorized user, however, can specify the VERSIONS parameter of the ALTERDS command to change that number of backup versions for a specific data set. An unauthorized user can specify the VERSIONS parameter of the HALTERDS command to change that number of backup versions for a specific data set with the same high-level qualifier as the unauthorized user.
  2. DFSMShsm can keep a maximum of 100 backup versions. Some versions may be for a cataloged data set with that name, some versions for uncataloged data sets with that name. The VERSIONS parameter indicates the number of backup versions kept for (1) the cataloged data set, and (2) the uncataloged data sets. DFSMShsm gives priority, if necessary, to versions of the cataloged data set. For example, if you specify SETSYS VERSIONS(15), when a backup version of the cataloged data set is created, no more than 14 versions will be kept for the uncataloged data set.
  3. If the number of versions in the VERSIONS parameter is decreased, and the EXPIREBV command is executed prior to the time the next version is created, all excess versions—whether cataloged or uncataloged—are deleted.
Parent topic: Optional parameters of the SETSYS command