Overview of the RUV backup function

To create RUV backups, you code and run the JCL to execute the RUV Backup function of the RUVZSM0 utility. In the control statement data set, you can specify individual files for backup with the BACKUP VSAM_IN or BACKUP_SEQ_IN command. You can specify a predefined group of files for backup with the BACKUP VSAM_GROUP or BACKUP SEQ_GROUP command.

Input and Output

As input, the Backup function supports sequential files, KSDS, ESDS, RRDS, and VRRDS VSAM base clusters. As output, the function writes one or more backup copies as sequential data sets. (In contrast, an Instant Snapshot copy creates a VSAM file without any alternate indexes.)

For VSAM files, if you specify the PREFIX(YES) keyword on the BACKUP statement, RUV writes each backup data set with a prefix. This prefix records physical information about the original VSAM base cluster. PREFIX(YES) is required for ESDS, RRDS, and VRRDS clusters. If you specify PREFIX(NO), which is valid for KSDSs only, RUV creates a flat-file backup that is identical to a copy that is created with the IDCAMS utility REPRO command.

For sequential files, all backups are not prefixed, no matter how the keyword is coded.

RUV can write backups to tape or DASD. RUV can stack backups for multiple files on a single tape volume (if space permits); stacking reduces the number of tapes that you must manage and store.

Registration

RUV implicitly registers an RUV backup by creating a backup registration record in the repository; it is not necessary to specify the REGISTER BACKUP command (as is required for registration of some other types of backups).

RUV automatically detects and restores RUV backups during restore and forward recovery processes. From the backup registration record in the repository, RUV obtains the timestamp relationship that it needs to select the correct archive files during recovery.