Windows XP "system" file corrupted

Discussion in 'Acronis True Image Product Line' started by jeanm, Feb 13, 2006.

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  1. jeanm

    jeanm Registered Member

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    Hello,
    Using TI 9, i did a restore from the last incremental backup, which link to a Windows XP error "c:\windows\system32\config\system" corrupted. Restoring the previous incremental backup (before the one giving the error), corrected the problem. Just a question why restoring this incemental backup ends up with a Windows error ?? (checking verify image and files after restore got the same problem). Is there some crtitical timing (or interaction with Windows), when TI save the "c:\windows\system32\config\system" file ??.
    Thanks for any answer.
    Regards
     
  2. TheWeaz

    TheWeaz Registered Member

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    Not entirely sure I understand the situation, but it sounds like the problem occurred between the time you did the second-to-the-last Inc and the last Inc. I’m guessing you did the restore because of the error.
     
  3. jeanm

    jeanm Registered Member

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    Thanks "TheWeaz" for your answer,
    Before the restore, Windows XP was functioning perfectly; I did not restore because of the error; i restored my C: disk after a software try/test which i did not want to keep (that is my method to avoid keeping garbage in Windows: Backup C:, Install and test the software, if i do not want to keep it, restore C:). I was using this method with Norton Ghost (without any problem), but as the incremental backup do not work in Ghost 9 (It is always doing a full backup loosing time and space), i went to TI.
    So i think that something happens at the TI incremental save time, between TI and Windows, which ends up with a "system" file saved corrupted.
    Any experience about that ??. Any TI 9 Guru to look at this ??
    During the next incremental backup i will avoid to concurently work with Windows and any application... (may be that is due to that..).
    Regards
     
  4. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello jeanm,

    Thank you for choosing Acronis Disk Backup Software.

    I'm afraid that it is rather hard to find out what exactly has caused the problem you encountered. However, the most probable reason is that some system files got corrupted during the image creation process.

    I would recommend you to disable any other software which requires the exclusive access to the hard drive (e.g. other backup software, antivirus software, partition and disk management applications, etc.) next time you will create an image.

    Please let us know if the problem appears again. We will investigate it and try to provide you with the solution.

    Thank you.
    --
    Alexey Popov
     
  5. jeanm

    jeanm Registered Member

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    Thanks Alexey for answering my problem.
    For the next backup (full or incremental), i will try to avoid using any applications concurently with TI process. But the only way to verify that the image is good is to restore the C disk and try to load Windows...other than that, TI verify it as a good image.
    How is managed by TI the fact that Windows can modify a file (Ex; System file which is in my case larger than 8.9 Mb) during the file save process, resulting to a file partially saved before modification and partially saved after modification, giving a file corrupted from Windows point of view ??.
    Can TI get the exclusive usage of this file (or all Windows system files) for saving purpose ??.
    Many thanks for any answer.
    Regards
     
  6. deerwood

    deerwood Registered Member

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    Hi jeanm,
    Somewhere on the TI site it is told, the mechanism is as follows:
    • TI locks partitions exclusively for a short time
    • TI remembers, which sectors are used on the partition (which doesn't take long, "just a few seconds" is told) in a bitmap (1111001010111...)
    • TI catches all writing operations to the disk, see below
    • TI unlocks the partition(s)
    • TI starts backup sector by sector and updates the bitmap accordingly (0000000010111...)
    • TI, catching all writing operations to the disk, buffers the original content of the sector, when the filesystem needs to overwrite it, and it is not backed up yet (bitmap is 1), then allows OS to overwrite
    • TI backs up the buffer instead of the modified sector, if it was overwritten in the meantime
    That way TI should do a backup of the partition/disk as of the time the locks were successfully placed, regardless of any other activity on the system including heavy activity like say defragmentation or installing new software.
    System files shouldn't be affected either and backed up without problems.
    By the way,this is very similar to what the Oracle database system does inside it's internal files, and my Oracle experience tells: it IS safe, even on system failure.
    hth, Georg
     
  7. Acronis Support

    Acronis Support Acronis Support Staff

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    Hello jeanm,

    To expand deerwood's explanation, I would also recommend you to take a look at this article explaining how Acronis True Image works.

    Thank you.
    --
    Alexey Popov
     
  8. jeanm

    jeanm Registered Member

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    Hello Deerwood and Alexey,
    Many thanks for your detailed explanations. I do not know how my SYSTEM file has been corrupted as the TI process seems to be reliable.
    I monitored the SYSTEM file for modification ("c:\windows\system32\config\system"), and found it is only modified (in my case) at Windows load time (power up). As my incremental backup is set to start at 8:00 AM with the check box "if the computer was turned off at the time the task....restarted", the incremental back up starts in fact with windows loading (time where the system file is modified by windows), as i power up my PC between 8:30 and 9:00 AM.
    Regards
     
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