Archiving refers to the process of copying the records from a statistics entry-sequenced cluster to another data set for long-term storage. The output of this process is an archived statistics file. You can write the archive file to a VSAM entry-sequenced cluster with the same characteristics as a statistics ESDS, or to a non-VSAM sequential file on DASD. The system does not store the statistics records in the ESDS in any special format. The system records each statistics record as a VSAM record in an ordinary VSAM ESDS. You can also write the archive file to a magnetic tape or a database table.
Archiving Using a Predefined Process
Using the DTF initialization parameter STAT.SWITCH.SUBMIT, you can specify that when the DTF switches from one statistics file pair to another, IBM® Connect:Direct® submits a predefined Process to archive the records in the previously active ESDS. IBM Connect:Direct submits this archive Process with a symbolic parameter indicating the data set name of the ESDS of the pair.
Timing the Archive
The archive must complete before IBM Connect:Direct needs to reuse the file being archived, that is, at the time of wrap-around of the file pair list. The completion of the archiving Process is important because IBM Connect:Direct erases the contents of the statistics file when the system switches to that file. In other words, archiving must complete within the time required for the file pair list to wrap. Normally, this condition does not present a problem.
Using the SELECT STATISTICS Command with Archived Statistics
IBM Connect:Direct for z/OS® provides a means of issuing the SELECT STATISTICS command against archived statistics. To make archived statistics available to SELECT STATISTICS, you must put the archived statistics in the format of a statistics file pair. You must make available a VSAM entry-sequenced cluster with a paired VSAM key-sequenced cluster containing the index information.
Maintaining an Archive File Directory
IBM Connect:Direct also provides the capability of maintaining a directory of statistics archive files. The directory is a VSAM key-sequenced file that contains a record for each archive file. Information in the record includes the data set name of the archive file and the range of dates and times covered by the archived records. Refer to VSAM Files DASD Requirement and Description in the for estimating space requirements when allocating the directory file. IBM Connect:Direct for z/OS Configuration Guide
This section explains the archiving related utilities: DGADARRT, DGADARBT, and DGADBKEY.
Sample Archiving Setup
Assume that you have the following requirements for archiving: