Complete backup range

This topic discusses the different types of complete backup ranges.

When an optical *PRIMARY volume to copied to an optical *BACKUP volume a special file called a Complete Backup Range is written to the *BACKUP volume. This file indicates the last time a backup was done. The system keeps backup control information for the volume as well as each directory on the volume. If the volume or directory was successfully backed up the Complete Backup Range will contain both a starting and ending date and time. When a range exists for an optical backup volume or directory, it has a specific meaning: The backup directory or volume has a copy of all the created or changed files within the date range that correspond to the primary directory or volume.

For example, volume BVOL1 is an optical *BACKUP volume for *PRIMARY volume PVOL1. BVOL1 contains directory /DIR1 that has a Complete Backup Range as follows:

Start date: 1/1/99
Start time: 09:00:00
End date: 1/30/99
End time: 22:00:00

Start Date: 1/1/99 Start Time: 09:00:00 End Date: 1/30/99 End Time: 22:00:00 This means that the system backe up all the changed or created files in /DIR1 on PVOL1 since 9:00 a.m. on 1 January 1999. The system backed up files to /DIR1 on BVOL1 at 10:00 p.m. on 30 January 1999. Any files that were created or changed on *PRIMARY volume PVOL1 in directory /DIR1 after 22:00:00 on 1/30/99 would not yet have been backed up.

This means that the system backe up all the changed or created files in /DIR1 on PVOL1 since 9:00 a.m. on 1 January 1999. The system backed up files to /DIR1 on BVOL1 at 10:00 p.m. on 30 January 1999. Any files that were created or changed on *PRIMARY volume PVOL1 in directory /DIR1 after 22:00:00 on 1/30/99 would not yet have been backed up.

Complete backup range for directories

The Complete Backup Range for a directory does not encompass all subdirectories of the directory. In other words, each directory has its own unique Complete Backup Range. For example, assume that directory /A has a Complete Backup Range of 1 March 1999 through 1 May 1999. This does not necessarily mean that directory /A/B has the same complete range. In fact, /A/B might have no Complete Backup Range at all. The complete range does not reflect a hierarchical range over all directories within that subtree.

The system updates the Complete Backup Range for a backup directory after it copies all eligible files in the primary directory.

Note: Use the SLTFILE parameter on the CPYOPT command to determine if a file is eligible. If you use *ALL, all files are eligible to copy. If you use *CHANGED, only those files that were created or changed since the last CPYOPT command are eligible. If you specified *NEW, the system copies files only if they do not exist on the target volume.

For example, FILE.001 gets copied on 1 March 1999 as a result of a complete backup of directory /DIR1. At this time /DIR1 is given an ending range of 1 March 1999. On 1 April 1999, the user has the system back up directory /DIR1 again by specifying SLTFILE(*CHANGED). However, the back up affects only the files that have changed. If FILE.001 has not changed since the previous CPYOPT command, this file is not eligible to copy. However, the system updates the ending range for /DIR1 to 1 April 1999 if none of the eligible files fail to copy.

Complete Backup Range for Optical Volumes

The Complete Backup Range for an optical volume is very similar to that of an optical directory. The complete range for a directory represents the relationship between the files in a backup directory and those in the primary directory. Likewise, the complete range for an optical backup volume represents the relationship between the files on an optical backup volume and those on the primary volume. You must back up all eligible files on a volume to update the complete range of the volume.

You can update the complete range for a volume only if the CPYOPT command specifies the FROMPATH(/) and CPYSUBDIR(*YES) variables. This ensures that the system will process all files on the *PRIMARY volume.