Explanation: FREQUENCY and SYSFREQUENCY are mutually exclusive, optional parameters specifying the number of days between backup versions of data sets. If the data set has changed since the last time it was backed up and the specified number of days (frequency) has elapsed since the last backup version was created, a new backup version of the data set is created during incremental volume backup. If, however, the specified number of days has elapsed but the data set was not changed, a new backup version of the data set is not created during volume backup unless you specified the TOTAL parameter of the BACKVOL command.
FREQUENCY(days) is specified to change the number of days between backup versions of the specified data set. For days, substitute a decimal number from 0 to 999. For example, if you specify days as 5, DFSMShsm backs up the data set if the data set has changed since the last time DFSMShsm backed it up and the latest backup version is at least five days old. If you specify 0, DFSMShsm creates a backup version of a changed data set every day that automatic backup runs.
SYSFREQUENCY is specified to revert to the value you specified with the SETSYS command or to the DFSMShsm default for the frequency of data set backup.
Defaults: None.