Incremental backup after a disaster recovery

Discussion in 'Acronis True Image Product Line' started by Spider3, Jun 15, 2007.

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  1. Spider3

    Spider3 Registered Member

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    Hi everyone,
    yesterday I had a failure on a RAID0 Disk containing about 25 Gb of Data. Luckly I had all the Acronis backup performed during the night. I've restored all the lost files successfully. For the restore, I've used the options to leave the original file date for the restored files (not to use the current date). Today i've checked the backup perofrmed during the night: the incremental image take 25+ Gb! That means all the files that i've restored yesterday have been backed up.
    Why, since the content of those files was not altered and the date was unchanged?

    Thank you,

    Mirto
     
  2. seekforever

    seekforever Registered Member

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    Image programs pay no attention to the file contents, dates or archive bit. They use a sector map of the disk and if a file is restored it looks like a change to TI even if the file was unaltered.

    For the same reason, defragging programs will cause large images because sectors are moved even though the data they contain is unchanged.
     
  3. Spider3

    Spider3 Registered Member

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    Mhhh..for the image (sectors based) I agree, but when Acronis perform a backup task (files based), the sectors should not matter.
    Additionally, in the Acronis Options I have checked the options to check only the date/size of the file for incremental/differential. And in my case, size and date was the same. What is this options used for then?

    thanks!
     
  4. MudCrab

    MudCrab Imaging Specialist

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    Did you check both dates after the restore? Perhaps TI is restoring the "Created" date/time, but the "Modified" date/time is being updated by Windows because the file is being rewritten.

    When backing up, I imagine that TI is checking the Modified date since that shows when the file was last changed.
     
  5. Spider3

    Spider3 Registered Member

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    Mmmh, going to check it this afternoon, let's hope is that. thanks ;)
     
    Last edited: Jun 19, 2007
  6. Spider3

    Spider3 Registered Member

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    I've checked the date as you suggested: Both Created and Modified are the original file date. With Acronis options checked to check only size and date, it has non sense that inremental backup backups all the files again.

    Please Acronis Support let me know if that's a normal behaviour and how can I avoid this, i don't want that after restoring 300 GB of DATA the next incremental backup will be like a full Backup

    Thanks!
     
  7. MudCrab

    MudCrab Imaging Specialist

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    I've done some searching and Acronis Support doesn't seem too explicit on what is actually being used to detect the changes in a files & folders backup.

    From this thread Incremental back-ups from moved files / folders
    From this thread File and Folder Backup Info Needed
    From this thread Does defragmentation affect file ("My Data") incremental backups?
    From this thread TrueImage 9 file backup?
    Some of these reference TI 9, but I doubt Acronis changed much in TI 10 for files & folders backups.

    Obviously, TI thinks the files have changed from the restore and so includes them in the next incremental/differential backup. I think I'll run some tests on this myself. If I find out anything interesting, I'll post it.
     
  8. MudCrab

    MudCrab Imaging Specialist

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    I have just run a small test with TI 10 (build 4,942). I created a files & folders full backup of a directory. Then I deleted the directory and restored from the backup file. The created and modified dates were correct. I then changed two files and ran an incremental backup. It only backed up the changed files and was finished in about one second.

    So it seems to work correctly in my test. Do you have any other programs running that might possibly have modifed the files with changing the dates?

    Did you use TI 10 (build 4,942) or a previous version?
     
  9. Spider3

    Spider3 Registered Member

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    Thank you a lot for your references MudCrab! Very kind.

    I am using Acronis True Image Server 9.1 for Windows, build 3920.

    I've performed some other tests too: you are right, it's working correctly as intended to be. No idea why did not worked after the disaster recovery.

    I can only suppose, may be that was caused because the whole backup was restored on the partition after i re-created the raid that was corrupted. (even if the location, size/date are the same, hardware id was different..or something like this).

    I'm not going to try if that's true or my boss will probably kill me ^^

    NB: I've observed that even if the files are restored with the original date, all the folders date have the date of the restore. well, not a big problem luckly, this is not affecting the incremental backup.

    thanks,

    Mirto
     
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