To configure a backup policy on a transaction volume, set the following items:
Number of Preservation Generations
The number of preservation generations refers to the maximum number of generations of backup data that should be kept.
The snapshot fast backup first releases the oldest generation from generation management. If a system failure or any other failure occurs while the backup is running, the oldest generation may have already been released and there may not be as many generations of backup data as required. Therefore, it is recommended that you re-execute backup immediately to create the required number of generations of backup data.
When performing snapshot type high-speed backup using only one preservation generation, it is recommended that you also back up data to a tape.
A synchronous high-speed backup operation releases the oldest generation from generation management after backup of the latest generation is completed. Therefore, the required number of backup volumes is equal to the maximum number of backup generations + 1.
Interval Days
Interval days refers to the time interval (in days) between successive backups.
A notification that backup is overdue is displayed if a period longer than the specified interval has passed since the last backup date, but a backup is not performed automatically in this instance even if you have specified the interval days between backups.
For information on setting a backup policy, refer to "3.4.7 Setting Backup Policy".
