Explanation: VERSIONS and SYSVERSIONS are
mutually exclusive, optional parameters specifying the maximum number
of backup versions to be kept when additional versions are made for
the data set.
VERSIONS(limit) is specified to
change the number of backup versions to be kept for the specified
data set. The maximum number of backup versions is limited to 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.
If you specify 0, DFSMShsm does not back up the data set.
SYSVERSIONS is specified to revert to the
value you specified with the SETSYS command or to the DFSMShsm default
for the number of backup versions to be kept for backup data sets.
Defaults: None.
Note: - Specify the SYSVERSIONS parameter only if a previous ALTERDS command
has changed the number of backup versions for this data set and if
you want to return to the number of backup versions specified on the
SYSVERSIONS setting. DFSMShsm determines the number of backup versions
in the following order:
- ALTERDS
- SETSYS
- DFSMShsm default
- If you reduce the number of backup versions with this command,
DFSMShsm does not delete existing backup versions when the ALTERDS
command is processed.
The existing excess backup versions will
be deleted to match the specified limit at the time a new backup version
is created for the data set. The EXPIREBV command can be used to
delete unwanted backup versions of data sets without creating any
new backup versions.
- DFSMShsm can keep a maximum of 29 versions or 100 versions, depending
on the BCDS record length. Some versions may be kept for a cataloged
data set with that name, and some versions kept for uncataloged data
sets with that name.
The VERSIONS or SYSVERSIONS 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
VERSIONS(15), when the 15th backup version of the cataloged data set
is made, no more than 14 versions will be kept for the uncataloged
data sets.