Question about differential backup

Discussion in 'Acronis True Image Product Line' started by Neverforget, Jan 26, 2006.

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  1. Neverforget

    Neverforget Registered Member

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    Arizona, USA
    My disk setup is as follows:

    1. Two internal 149 GB harddrives in a RAID 1 (mirrored) configuration divided into 3 partitions as per configuration from Polywell:
    C:\Windows XP and program files
    D:\Documents and music files
    G:\Backup of operating system to restore computer to original state
    2. One external hardrive to use to do an:
    Initial full backup of all three partitions;
    Weekly differential backup of C:\ and D:\ partitions, because the G:\ partition will never change.

    Any problems with this regimen in terms of restoring if necessary?
     
  2. Rodb

    Rodb Registered Member

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    Looks a reasonable approach, however I have a question about diffferential backups as well and I expect whoever can answer your question 100% will also be able to answer mine.

    TI seems to create more than one differential backup which seems a little odd to me, I always assumed that differential meant only one file was needed to added to the base file to restore the image.

    My approach is to take a base image, and a differential. From then on, I will delete the differential file and recreate it at each differential backup. However as I have two removable disks I need to know that the differential is created by TI actually comparing the base with the source and not from some other remembered data. Otherwise when I change disks (weekly) the differential may be wrong(as the base will be slightly different) , but if it always looks at the base then I will be OK.

    One more question, when verifying a base image does TI also automatically verify the differential file as well?

    Forgot, I am using build 2337, the latest available.

    Apologies for the long question, but I have only bought TI recently and I like its ease of use, just need to make sure I use it properly as well..
     
  3. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello Neverforget,

    Thank you for choosing Acronis Disk Backup Software.

    We do not expect any problems with your scenario of image restoration. However, we recommend you to verify the integrity of your images by using Check Archive tool and try to restore one of your image in order to make sure that the program works on your computer without any problems.

    Please find more detailed information on how to use Acronis True Image 9.0 in the respective User's Guide.

    If you have any further questions please feel free to ask.

    Thank you.
    --
    Tatyana Tsyngaeva
     
  4. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello Rodb,

    Thank you for choosing Acronis Disk Backup Software.

    I'm afraid that I do not understand your question correctly.

    Could you please clarify what exact actions you want to perform?

    I'm afraid no. You should verify the differential image integrity manually.

    You can find more information on how to use Acronis True Image 9.0 in the respective User's Guide.

    Thank you.
    --
    Tatyana Tsyngaeva
     
  5. Rodb

    Rodb Registered Member

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    Apologies, just re-read my post and it is ambigouous.

    I have two removable disks for backup, disk A and disk B. On each I have taken a full image of the C: drive and now take an automatic differential image at shutdown. The .tib filenames on both disks are the same.

    I want to verify that if disk A is in the PC the differential will be between the image on disk A and C: as it is running.

    What happens if I change my disks and put in disk B. When I take a differential will it be between the image on disk A and the C: drive or will it be between the B image?

    As long as TI always generates the differential by comparing the full image and the live C: drive it will always work well. I am just concerned that TI might keep another record of the image elsewhere to use for generating the differential.

    Hope that makes sense!

    If the differential .tib file is always generated as a result of comparing the base .tib file and the live C: drive I wont have a problem.
     
  6. Menorcaman

    Menorcaman Retired Moderator

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    Hello Rodb,

    I'm sure Acronis Support or other user will correct me if I'm wrong but I believe that, in simple terms, TI will compare a "thumbprint" of used sectors on the source disk with the "thumbprint" of the Full image on the destination disk (whichever one happens to be connected at the time) and create a differential image equating to the difference between the two.

    Regards
     
  7. Rodb

    Rodb Registered Member

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    Hi Menorcaman,
    Thanks for that, my concern was that TI might have kept another copy of data somewhere to use for generating the differential file.

    My backup regime works this way, after the full image was created manually, I have TI set up to save a differential on shutdown.
    On startup I have an automated task that copies the differential file to my server and then deletes it off the PC. This way I always have a differential file which is number 2 and all seems to work well. I have tested it, by deleting my primary partition and doing a full restore, works well.

    So its now all automated and reliable. Every month or so I will manually update the full image to keep the size of the differential down in size.

    Regards
     
  8. Menorcaman

    Menorcaman Retired Moderator

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    Hi Rodb,

    Nice work - glad everything checked out OK.

    Happy imaging and, hopefully, not too much restoring ;) :D

    Regards
     
  9. Neverforget

    Neverforget Registered Member

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    Arizona, USA
    Thanks, everybody, for all the information and ideas.
     
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