Explanation: DAY is an optional subparameter of DUMPCLASS specifying the target day of the dump cycle for this class. DAY restricts that this class be targeted during automatic dump processing only on the specified day of the cycle.
DUMPCLASS(DAY(day)): For day, substitute a decimal number to specify the target day of the dump cycle. A value of zero indicates that a previous association with a day in the dump cycle should be removed. Any other numeric value must be from one to a value less than or equal to the number of days specified in the dump cycle. day must be a ‘Y’ day specified in the DUMPCYCLE parameter. If a frequency is also specified, the frequency must be satisfied before the class is chosen. Full-volume dumps requested by command, however, are processed independently of the DAY specified.
DAY can be used instead of the FREQUENCY parameter, if you desire to dump to this class every cycle repeat. DAY allows a subset of the primary volumes to be dumped on one day and another subset to be dumped on another day. For example, if the primary volume subsets are defined by two dump classes and the dump classes are identical except for the DAY parameter, one subset of primary volumes can be dumped on one day and the other subset of primary volumes can be dumped on another day. The primary volumes can retain the same frequency and retention characteristics.
DUMPCLASS Defaults: If the DAY parameter is not specified for the DUMPCLASS, determination of whether to dump a volume is based on other parameters. If the FREQUENCY parameter criterion is met, a volume will be dumped on each ‘Y’ day specified in the DEFINE DUMPCYCLE.