Before beginning this phase, each host obtains from SMS a list of the volumes in copy pools and storage groups that have the AUTODUMP attribute = Y. It also obtains a list of the dump classes to which the volumes in each copy pool and storage group are to be dumped. DFSMShsm then starts automatic dump tasks in each host, until each host has as many dump tasks as are specified by the MAXDUMPTASKS parameter of the SETSYS command. Volumes in copy pools are processed first.
The following process is followed first for volumes with dumps that can be stacked, then for the remaining volumes: If the maximum number of dump tasks is reached and there are still more volumes to process, DFSMShsm waits for any already-active volume dump task to complete dumping its current volume. When a volume dump task completes dumping its current volume, it begins dumping the next DFSMShsm-managed volume with the automatic dump attribute. This process continues until all DFSMShsm-managed volumes have been dumped, or the quiesce time is passed.
When processing each volume, DFSMShsm checks the FREQUENCY and DAY subparameters specified in the dump classes to which the volume is assigned. If the DAY corresponds with the day of the dump cycle, and the time since the volume was last dumped is not less than the FREQUENCY specified, the volume is dumped to that dump class. The determination of frequency of dumps includes dumps made by command as well as automatic dumps.
As an example of the effect of the DAY and FREQUENCY subparameters, it has been stated that you are beginning this description of processing for day 28 in a specific dump cycle. Consider volume SG2002 in Figure 1. Storage Group 2 specifies that the volumes be dumped to dump classes ONEWEEK and TWOWEEK. Now assume that someone had issued a command to dump SG2002 to dump class ONEWEEK on day 16 of the dump cycle. SG2002 would not have been dumped on day 21, as was specified by ONEWEEK for that day, because less than seven days had elapsed since it was last dumped. It is now day 28. Dump class ONEWEEK specifies that you can dump the volume to it every seven days, so that SG2002 is dumped to dump class ONEWEEK.
Now consider volume SG4001. Storage Group 4 is dumped to dump classes ONEWEEK and FOURWEEK. Dump class FOURWEEK specifies that volumes can be dumped to it only on day 28 in the dump cycle. Therefore, SG4001 is dumped to dump class FOURWEEK because it is day 28 in the dump cycle.
If the maximum number of dump generations has been reached and another dump is to be performed, the oldest generation is deleted. If the RETENTIONPERIOD has the attribute of NOLIMIT, a dump copy is automatically deleted only when it is a member of a dump generation that exceeds the maximum of 100.
During dump processing, if a dump class is not eligible because of FREQUENCY, it is not dumped regardless of its REQUIRED/OPTIONAL status. When a copy pool dump is being resumed, FREQUENCY is not considered. When a dump class is not added to a copy pool version because it has not met the FREQUENCY criteria, it can be added outside of the automatic dump window with the FRBACKUP DUMPONLY command
Automatic dump attempts to dump every volume in a copy pool. If any of the volumes fail, the dump version is marked as a partial success. If automatic dump terminates early , it issues message ARC1818I indicating 'n volumes of copy pool cpname did not complete the dump process.' This message is issued once for each copy pool that has not completed automatic dump processing. Automatic dump continues to check for the end of the automatic dump window between each volume.
Since a copy pool is composed of one or more storage groups each having their own Auto Dump Y|N settings, it is suggested that these individual storage groups all have Auto Dump=N defined, unless there is a specific need for dumping volumes at both the copy pool and the storage group levels.