Question about Differential Backup....

Discussion in 'Acronis True Image Product Line' started by CDreier, May 18, 2006.

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  1. CDreier

    CDreier Registered Member

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    I did a Full Backup Archive of my HD several weeks ago. Today I did a Differential Backup of the same HD. I've found that the Differential is almost the same size as my original Full Backup Archive and that the 2 file names are Disk Image.tib and Disk Image2.tib. I'm not sure whether I've indeed created a Differential, or whether I've somehow simply reimaged? What does it sound like to you? Thanks!
     
  2. TheWeaz

    TheWeaz Registered Member

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    Those names are consistent with FULL/DIFF backups.
    A lot of data can be added/modified/moved in “several weeks”, so the size of a DIFF may get large.
     
  3. CDreier

    CDreier Registered Member

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    Thanks for the quick reply and for answering my question. Here's another one. If, at some point, I decide to simply start over with a new Full Backup Archive, is it okay to just reformat my external hdd (where the archive is kept) and then start with the new Full Backup, or is there something else to do instead? Thanks....
     
  4. TheWeaz

    TheWeaz Registered Member

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    Why reformat?
    If you rerun the FULL backup task, it will write over the existing one. This will orphan the DIFFs and, therefore, they cannot be used to restore. When you rerun the DIFF task, they too, will overwrite the existing ones.
    Or you could just delete them all and start again.
    Or, if you want to keep the current backups, just edit the FULL & DIFF tasks and give the image files a new/different name.
     
  5. CDreier

    CDreier Registered Member

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    That answered my questions. Thanks for the great help!
     
  6. Stevis

    Stevis Registered Member

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    I'm a bit confused about restoring differential backups. I just restored an original full backup to an unformatted new hard drive with success. However, the differential backups I've done since (26 to be exact) were not restored. Do I need to restore each differential separately in order, or can I just restore the latest one and get all the previous differential backups restored automatically? Second, once I get everything backed up to the current state, can I just do a new full backup and delete all the previous differential backups?
     
  7. seekforever

    seekforever Registered Member

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    The last differential backup contains all the changes since the full image was created. The intermediate ones are not required although you could use them to pick a point in time to restore to. Unless it's been fixed, I think TI wanted all the intermediate diffs in order to do a validate though (?) .

    After you do your restore you should do a new full since a differential done at that time will be about the same size. Imaging programs look directly at in-use sectors and if the data has moved it is seen as a change. When you restored everything was likely moved. You can delete the old ones but if you don't need to, keep them, they may come in handy. I personally don't fly with only one backup.
     
  8. CDreier

    CDreier Registered Member

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    Perhaps that may be why my "differential" was almost as large as the original image. I had done a defrag using O&O's Professional using the "name" method. I'm sure that virtually all of the data had been moved. Agree?
     
  9. seekforever

    seekforever Registered Member

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    Yes, defragging is known to cause large differential or incremental backups. Defrag then do a new full backup is the accepted practice and avoid defragging while you are doing a series of incr/diff backups.
     
  10. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello Stevis,

    Thank you for choosing Acronis Disk Backup Software.

    Just would like to confirm that, as seekforever said, in order to check data from the differential backup, you must have the initial full backup as well. However, if you created several differential or both incremental and differential backups based on the same full backup (and therefore, in the same folder), you will need all of these successive backups to validate the archive.

    As it was already mentioned, to restore data from the differential backup, you must have the initial full backup as well.

    Thank you.
    --
    Aleksandr Isakov
     
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