Specifying how many versions to keep for each backed up data set
For non-SMS-managed storage, the number of backup versions to retain
is a DFSMShsm host-wide specification.
Note: You can use
the (H)ALTERDS command to specify a different value from the DFSMShsm
host-wide default for individual data sets.
As with SMS-managed storage, depending on the record length that
is used to define the BCDS, DFSMShsm can maintain up to 29, or up
to 100, backup versions of any data set. Within that upper limit,
the VERSIONS parameter of the SETSYS command controls the number of
backup versions to be retained. For the example system, the following
command is added to the ARCCMDxx member for
each DFSMShsm host:
SETSYS VERSIONS(5)
If you use the RETAINDAYS keyword when you create a data set backup copies, and active backup copies with an unmet RETAINDAYS values are rolled off, DFSMShsm maintains them as retained backup copies. DFSMShsm can maintain more than enough retained copies for each data set to meet all expected requirements.
Related reading
- For more information about how record length affects the number of backups, see z/OS DFSMShsm Implementation and Customization Guide.
- Specifying the number of days to retain a backup copy of a data set.
- Creating retained backup copies.