ABACKUP command

Two options are available with the ABACKUP command. You can choose to verify the contents of the aggregate backup without actually backing up any data sets, which is the same as performing a test run of aggregate backup. Then, when you are ready, you can perform the actual backup.

When you enter the ABACKUP command with the EXECUTE option, the following tape files are created for later use as input to aggregate recovery:

Output data set tape files, which contain copies of the backed up data sets, as follows:
- "D" data file, which contains copies of level 0 data sets that have been backed up.
- "O" data file, which contains copies of migrated data sets or user tape data sets that have been backed up.
Note: The "D" file is created when you have level 0 disk data sets in the INCLUDE list. The "O" data file is created when you have user tape data sets or migrated data sets in the INCLUDE list. If you requested stacking for the ABACKUP output files and you do not specify an INCLUDE statement, a dummy "D" and "O" file is created. If you did not request stacking for the ABACKUP output files and you do not specify an INCLUDE statement, no "D" or "O" files are written. For the format of these files, see Data files.
A control file. This file contains control information needed by aggregate recovery to verify or to recover the application’s data sets. The control file also specifies which ACCOMPANY and ALLOCATE data sets should be cataloged or allocated at the recovery site.
An instruction/activity log file. This file contains the instruction data set, which is optional. The instruction data set contains the instructions or information that may be needed at the recovery site. A copy of the activity log is also written to this file if the activity log is directed to DASD by the SETSYS ABARSACTLOGTYPE command.
Note: This file is created only if an instruction data set name was specified in the aggregate group, or the ABACKUP activity log was allocated on DASD.

Also, aggregate backup creates the following:

Filter output data set—Created if requested with the FILTEROUTPUTDATASET parameter of the ABACKUP command.
Activity log—Contains messages issued during aggregate backup processing.
Functional statistics record (FSR)—Containing additional aggregate backup processing information. This includes records of the amount of CPU time used for processing ABACKUP and ARECOVER requests that can optionally be written as an SMF record if the installation specifies SETSYS SMF(smfid).
Note: If the total number of volumes used for the data files, control file, instruction data set, and accompanying data set exceeds 5000, an extension FSR is created for the aggregate. Each extension FSR contains a maximum of 5000 volume serial numbers. In addition, each extension FSR has the constant “CONT” at offset X'7C'. There are as many extended FSRs as necessary to hold all volume serial numbers processed by a particular aggregate. The extension FSRs repeat all aggregate information except the volume serial number lists.
An ABARS activity record (ABR) is created in the BCDS. This record contains information related to an aggregate backup and recovery performed on a particular aggregate group.

Rule: You must have a BCDS when performing an aggregate backup or aggregate recovery.