Incremental Backup

With the mode "Incremental Backup" it is possible to save only new files and files that have changed since the last (full/partial) backup. A full backup is always used as a reference to determine which files should be saved. The list of all files to be saved and the date of the last backup is extracted from this full backup. This date will be compared with the date of the last incremental backup. Only entries in the file list which have a newer date will be saved.

An existing backup job (which is used as reference) must be selected in order to do an incremental backup. For this reason the file selection is replaced by the list of existing backup jobs. This is exactly the same list that is shown in the JobQueue window of SIEGFRIED BACKUP. The only difference is, that all none backup jobs are filtered. Only a single backup job can be selected as a reference for an incremental backup.

SIEGFRIED BACKUP automatically uses the title of the selected full backup job as the new title for the incremental backup.

An incremental backup always deactivates the overwrite mode of the destination drive!




For example:

A full backup should be created every sunday. Only those files should be saved that have been modified on every other day of the week.

Two jobs must be created to do such a backup. The first job is a full backup. All drives/directories/files to backup must be marked. "Overwrite" should be selected at the destination setting to save backup space.

The repeat interval of the full backup is set to 1 day. Monday through Friday should be excluded in the selection which confines the full backup to Sundays.

A unique title should be set (i.e. "Backup of my MP3 files") in the backup start window.

After the job is started the second job, the incremental backup, can be created. Select the backup mode "Incremental". The backup window now shows all backup jobs instead of the file list. Select the job with the title "Backup of my MP3 files" as a reference for the incremental backup.

The destination of the incremental backup should be the same as in the full backup. This isn't absolutely necessary, but it's a good idea to to simplify keeping track of backups that belong to each another.

The one day repeat interval is used in the scheduler. Sunday should be excluded. This ensures that the incremental backup runs on every day except Sunday.

The backup start window automatically uses the title of the full backup. The backup proceeds as follows after the job start:

The first full backup starts on Sunday. It saves all selected files. On monday the incremental backup is started. The file list and date of the last backup are exrtracted from the job data of the full backup. The date will be compared with the date of the last incremental backup. Because there was no incremental backup running for this job yet, the date of the last full backup is used as reference. By using this date all entries of the file list are removed which are older (not modified). The cleaned file list is used for the backup. The saved data is placed in the same destination as the full backup (the data of the full backup will not be overwritten).

On Tuesday the incremental backup starts again. The file list and date of the last backup is extracted from the full backup job. The date will be compared with the date of the last incremental backup. In this case the date of the incremental backup is used because it's the newer one (full backup was running on Sunday and incremental on Monday). The file list is cleaned using the date and then the backup starts using the new list.

The above procedure will be repeated every day until next Sunday. Only entries that have been modified from one day to the next will be saved.

On next Sunday the full backup starts again. If "overwrite" is activated, all backup data of the full and incremental backup jobs will be deleted because they are placed at the same destination. After that a new complete backup is created.




A full backup with an incremental backup is a combination that uses the lowest amount of destination space. But it's also true that a restoration of the saved data is more complicated. To restore a complete backup with incremental backups, the full backup must be restored first followed by all incremental backups in the correct order of their creation.