Volume type *BACKUP

 

This section discusses the *BACKUP volume type and the unique backup process that are associated with a *BACKUP volume.

Remember that using Copy Optical (CPYOPT) command to a *BACKUP volume is no longer the suggested way of backing up your volumes because of the time required. Duplicate Optical (DUPOPT) command is the recommended way of backing up your volumes.

The *BACKUP volume type supports the backing up and protection of information from optical primary volumes. The system does not allow user programs or APIs to write to optical backup volumes. Only a limited set of optical commands can update backup volumes. After the system creates a directory or file on an optical backup volume, the only way to delete it is to reinitialize the volume. Doing this prevents either accidental or intentional deletion.

Backup volumes and directories contain a Complete Backup Range file, which contains date information about prior copy requests to the optical backup volume. These dates are helpful in determining the contents of backup directories and volumes with respect to the contents of their primary counterparts. These control dates make it easier to recover by providing a time checkpoint. Each backup directory has its own control dates. Each backup volume also has its own control dates, which include:

• Complete starting date and time

• Complete ending date and time

• Last changed date and time

The system writes these dates to the backup volumes in a reserved file within each backup directory. Since the system writes the dates to the media, the backup volumes are self-contained. Not only is the backup data on the media, but the recovery information is there as well.

• Completing backup range
  When an optical primary volume is copied to an optical backup volume, a special file called a Complete Backup Range is written to the backup volume.
• Completing backup range: Starting date and time
  You can specify a starting date and time on the Copy Optical (CPYOPT) command.
• Completing backup range: Ending date and time
  The CPYOPT command does not allow you to specify an ending date and time. The system always uses the date and time of the copy request as the ending date and time.
• Completing Backup Range: Last changed date and time
  Using the CPYOPT command causes the system to write the last changed date and time of an optical backup volume or directory.
• Example: Copying to optical type *BACKUP volue
  This example shows the system that backs up the primary volume VOL01 to the backup volume BKP-VOL01.
• Converting an optical type *BACKUP Volume
  Use the Convert Optical Backup (CVTOPTBKU) command to convert an optical *BACKUP volume to an optical *PRIMARY volume.

 

Parent topic:

Copy Optical (CPYOPT) command