When the current recording data set cannot accommodate any more records, the SMF writer routine automatically switches recording from the active SMF data set to an empty SMF data set, and then passes control to the IEFU29 SMF dump exit. The operator is then informed that the data set needs to be dumped. (For more information on the IEFU29 exit, see the z/OS MVS Installation Exits book.)
SMF data sets cannot be shared across systems. IBM® does not recommend that the SMF data set dump program be run from one system in an attempt to clear a SMF data set used by another system.
When notified by the system that a full data set needs to be dumped, the operator uses the SMF data set dump program (IFASMFDP) to transfer the contents of the full SMF data set to another data set, and to reset the status of the dumped data set to empty so that SMF can use it again for recording data.
The SMF data set dump program dumps the contents of multiple VSAM or QSAM data sets to sequential data sets on either tape or direct access devices. The SMF data set dump program allows the installation to route different records to separate files and produce a summary activity report. This report is described in Creating the summary activity report. The job control language (JCL) to execute the SMF data set dump program is described in Running the SMF data set dump program.
The SMF data set dump program copies the input data sets to the output data sets. During the copy process, the SMF data set dump program creates two SMF records and writes them to every output data set: a dump header (record type 2) at the beginning of the data set and a dump trailer (record type 3) at the end of the data set.
The SMF data set dump program writes a message to the SYSPRINT data set for all input and output data sets and includes the names of the data sets in the message.