FREQUENCY(days) | SYSFREQUENCY are mutually exclusive, optional parameters used to specify the minimum number of days between consecutive backup versions of changed data sets during incremental backup. If you have changed a data set since DFSMShsm created the latest backup version and the specified number of days has elapsed, DFSMShsm creates a new backup version of the data set during automatic backup. If the specified number of days has elapsed but you have not changed the data set, DFSMShsm does not create a new backup version of the data set during automatic backup.

FREQUENCY specifies the minimum number of days that must elapse between two consecutive backup versions of the data set during incremental backup. For days, substitute a decimal number from 0 through 999. For example, if you specify days as 5, DFSMShsm backs up the data set providing you changed the data set since the last backup and the last backup version is at least five days old. If you specify 0, DFSMShsm creates a backup version for a changed data set every day in the backup cycle during automatic backup.

SYSFREQUENCY specifies that you want DFSMShsm to back up the specified data set at the same frequency that the system programmer specified. Use this parameter only if you issued a previous HALTERDS command to change the frequency of backup versions from the frequency specified by the general DFSMShsm parameter value.