Copying and moving tape data

You may have a need to copy or move tape data from one tape to another, for reasons such as replacing error prone media or moving to new technology. You can do this by using a tape copy utility that uses DFSMSrmm services to correctly copy and re-stack tape data sets while preserving the data set attribute settings and, optionally, set retention periods for the source data set, copy data set, or both. A tape copy application can notify DFSMSrmm that a newly created tape data set is a copy of an existing data set and that the target data set is actually the source data set and, optionally, that the source data set is no longer required. That is, the data set has effectively been moved.

A tape copy application might be a product such as IBM® Tivoli® Tape Optimizer (ITTO) or some JCL you create to copy a tape data set. If you use your own JCL and a utility like IEBGENER you can use the RMM CHANGEDATASET subcommand with the COPYFROM operand to complete the copying of the source data set attributes. However, a tape copy application can select the method used to communicate with DFSMSrmm.

DFSMSrmm provides two methods that support copying and moving tape data:

Once the target data set has been created, the tape copy application can use the CHANGEDATASET COPYFROM subcommand to copy all applicable attributes from the source data set to the target data set. DFSMSrmm determines which attributes are to be copied. Retention of the source data set can be specifically set. Retention of the target volumes and data sets can be selected at the volume set level, and even switched between VRSEL and EXPDT retention methods.
During the creation of the target data set, tape copy application programs can use the EDG_EXIT100 installation exit to copy all applicable attributes from the source data set to the target data set. Retention of the target volumes and data sets can be selected at the volume set level, and even switched between VRSEL and EXPDT retention methods.

Using the DFSMSrmm COPYFROM support you can ensure that all applicable data set attributes are copied and avoid using multiple RMM subcommands to modify only the attributes supported via the subcommands.

DFSMSrmm does a minimum of validation to ensure that the source and target data sets are the same. The validation differs depending on whether the copy is done with the CHANGEDATASET COPYFROM subcommand or the EDG_EXIT100 installation exit.