Full Backup with differential backup

Discussion in 'Acronis True Image Product Line' started by jjocsak, May 13, 2007.

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  1. jjocsak

    jjocsak Registered Member

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    I first started with a full backup of my c: drive. Then I have a task to do a differential backup every week. I have the following list of files after a few weeks.

    http://JJOCSAK.smugmug.com/photos/152404714-L.jpg

    My question is can I delete all the differential backups except for the last one?
    If so how can I get TI to do that automatically?

    It seems to me they are safe to delete since the differential backup works off the full backup, so it must reference that every time it does a diff backup.


    Jeff
     
  2. foghorne

    foghorne Registered Member

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    If you create a new full backup (e.g. on a schedule) this will overwrite the existing one, and the diffs will become orphaned. As you create more diffs the orphaned ones will be overwritten.

    Logically and intuitively correct. However the real world is a harsh place. If you delete any of the intermediate differentials, validations on any remaining ones will fail. You can still use them to restore, but they will not pass validation.

    This seems to be because the validation processing is based on the same scheme used by incrementals, and it requires all diffs in the chronological chain to be present.

    I think Acronis think of this behaviour as a quirk, I call it a bug :)

    F.
     
  3. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello jjocsak,

    Thank you for choosing Acronis Disk Backup Software.

    Please note that you could you pre\post commands of Acronis True Image to execute batch file, which deletes backups you do not need automatically before/after backup process. Additional information can be found in the chapter "Pre/post commands" in the respective User's Guide.

    If you use Acronis True Image 10.0 Home you can use Backup Location to store backup archives. Backup Location provides automatic archives management function and consolidate or delete the oldest backups in the Backup Location. Check chapter 3.5 "Acronis backup locations" in the Acronis True Image 10.0 User's Guide for details. I would also recommend that you have a look at this thread <delete inkremental Backups after a defined time> to find more information about the Backup Location.

    In addition, as foghorne mentioned, if you created several differential or both incremental and differential backups based on the same full backup, you will need ALL of these successive backups to validate the archive. To restore data from a differential backup, you do not need other differential backup archives, you must have the initial full backup.

    Thank you.
    --
    Aleksandr Isakov
     
  4. jjocsak

    jjocsak Registered Member

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    Thanks, I understand it now.

    Jeff
     
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