Abstract: The variable-level backup scheduling method employs a schedule in which backups are performed at set times but the level of backup performed is determined from the condition of the system at the time of backup. Under this method, user-supplied parameters stored in level-tables allow a determination of the appropriate level of backup to be performed. If the data in the scheduled level of backup has not been modified in a sufficient amount under the supplied parameters, then the backup scheduling method determines whether a specified higher level backup is appropriate. If the evaluation of the higher level backup results in a determination that not enough data has been modified, the next level is evaluated. This process continues until the criteria for backup have been met or the level that has been predetermined to be the least amount of data to be saved has been reached.

Abstract: A mechanism for performing retroactive backups in a computer system is presented. The retroactive backup mechanism employs a backup policy dictating that certain backups are to be performed at set times and for set backup levels, but subject to user-defined selection criteria so that the backups are of a retroactive nature. The selection criteria comprises a retroactive backup date upon which the scheduled backup is made effective. It is selected to correspond to the backup date of a previous backup or save set. Alternatively, the retroactive backup date upon which the scheduled backup is made effective is determined by controlling the amount of data to be backed up. Thus, the selection criteria comprises a maximum size threshold, selected by a user or system administrator as the amount of data that can be backed up in an allotted backup time. The retroactive backup copies to a new save set only data that has not been modified or deleted since the date indicated as the retroactive backup date.