sector-by-sector imaging - to the attention of Mr. Alexey Popov

Discussion in 'Acronis True Image Product Line' started by CalamityJake, Dec 27, 2005.

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  1. CalamityJake

    CalamityJake Registered Member

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    Hi,

    I'm new to TrueImage, previously been using Ghost. I turned to looking for alternatives after finding it impossible to do *proper* incremental backups in a certain particular situation, which I'll describe at the end of this thread.
    For now, I'll just say that TrueImage doesn't solve it either, and this is because of the way sector-by-sector imaging is (not) done by the ironically named "TrueImage".

    Here are two statements from Mr. Alexey Popov, a support team member, posted on two different occasion, statements that besides being expressed in a very clear, enlightening manner, are perfectly contradictory as well:
    1) from https://www.wilderssecurity.com/showthread.php?t=112864&highlight=sector-by-sector

    "Please be aware that when Acronis True Image 9.0 creates a disk\partition image it does a sector-by-sector backup regardless of whether the file system of the backed up partition is supported or not (corrupted).

    The only difference between these two cases is that when Acronis True Image 9.0 recognizes the file system (I mean that the file system is known by Acronis True Image 9.0 or in other words - supported) then it backups only the used sectors of the backed up disk\partition. Otherwise (in case of the unsupported or corrupted file system), there is no way for Acronis True Image 9.0 to determine which sectors are actually used and which of them are not, so it creates a sector-by-sector image of all sectors of the backed up disk\partition including so-called "free" space."

    And

    2) from https://www.wilderssecurity.com/showthread.php?t=110559&page=2&highlight=incremental restore

    "Please be aware that Acronis True Image 9.0 creates sector-by-sector images only in case of the corrupted or unsupported file system. It therefore does not restore files to the exactly same sectors they were residing at the moment you have created an image. However, it does not affect operating system functionality in any way."

    Now I would appreciate a confirmation from you folks, that it's not just my non-native English and these two are indeed opposite, that is, in the first statement, backup is always done sector-by-sector, with the observation that when the file-system is known and not corrupted, only used sectors are copied, whereas in the second statement, the backup is done on a sector-by-sector basis only when the filesystem is unknown or corrupt.

    Also, I would appreciate a final statement from the support (or - why not - development) team.

    And here's the problem I'm having with incremental back-ups:
    Usually, after I install the OS, I make a full back-up of the system partition and then an incremental back-up every once in a while, after installing certain programs. The thing is, I'm of a very curious/experimental nature and install a lot of crapware before choosing the right software for a particular job. Therefore, I revert very often to partition states reflected by the various incremental backups I made, in which situation, after restoration, I would like to go on experimenting, creating new incrementals from the restore point and discard the existing ones from that point up. The thing is, if I try an incremental back-up just immediately after a partition restoration, the resulting incremental image is about the size of the full back-up.
    This means that, either the initial disk sector layout is not exactly "mirrored" in the image file, or at restore time, the partition is not restored according to the exact layout supposedly stored in the image file.

    It can be true though, that the image is obtained after reading the hdd at sector level, (and not using OS-provided "descriptor" techniques), only the sectors are rearranged, which is sometimes not desirable and should at least be configurable by user.

    Thanks for listening and I would appreciate any comment.
     
  2. WonderWrench

    WonderWrench Registered Member

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    A incremental backup images what has physically changed on the drive, not file by file. So just doing a defrag could cause incremental backups to be quite large. IMO useless I do only full backups.

    As far as the sector-by-sector backup goes I think the first statment is writen poorly. The second one is correct.
     
  3. CalamityJake

    CalamityJake Registered Member

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    It's definitely not defragmentation which of course I didn't do before taking the incremental image, and neither did I run any disk-tampering program for that matter. It's simply that TrueImage restores an image in such a way that an immediately subsequent comparison between that image and the disk partition results in virtually all sectors being different.
     
  4. Menorcaman

    Menorcaman Retired Moderator

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    Hello CalamityJake,

    Are you using the latest build (2323) of True Image 9? Earlier builds contained a bug, whereby the first incremental after a full image invariably ended up the same size.

    The term "sector-by-sector" is somewhat misleading when used in the context of a normal image (be it full, differential or incremental) and should be changed to "in-use sectors". Check out this previous thread titled <OK, just what is True Image 9>.

    Regards
     
  5. CalamityJake

    CalamityJake Registered Member

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    Hi Menorcaman,

    Yes, I am using build 2,323.

    Although your proposition of the "in-use sectors" term sounds reasonable at first, in the end I must agree with Howard Kaikow, that "sector by sector" copying should not be talked about in the context of filesystem-specific backup. As he put it, " [..] "in-use" "images", [..] may omit significant portions of a logical drive, if that logical drive has more than one file system."

    Now that we're through with understanding what kind of images TrueImages, the problem of the exact restoration (or lack of, thereof) of those in-use sectors remains. Any answer on that from the support team?
     
  6. bobdat

    bobdat Registered Member

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  7. CalamityJake

    CalamityJake Registered Member

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    Anyone from Acronis willing to share some light on the incremental-after-restore subject? At least would you acknowledge the bug?
     
  8. Menorcaman

    Menorcaman Retired Moderator

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    Not sure how much more info you require over and above that which I provided in Post #8 in this previous thread titled <Incremental backup question> o_O

    Regards
     
  9. Howard Kaikow

    Howard Kaikow Registered Member

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    My ears got red, I guess because of the reference to the thread I started.

    I am still not satisfied with the Acronis response.
    Indeed, they still have not responded adequately to all the questions in that thread.
     
  10. CalamityJake

    CalamityJake Registered Member

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    To Menorcaman:
    1) You say in that post that "Acronis Support have previously stated that when TI restores an image it doesn't necessarily write to the same sectors that the image was created from." Could you please post a link to that statement, or indicate where it can be found in the help file?
    2) I would like Acronis to state whether or not a reasonably-sized incremental image can be obtained immediately after a restore, and if not, acknowledge this as a BUG and admit that their "optimization" of disk sectors layout was not a good idea and people who require exact disk imaging/restoration are indeed having at least one good reason for that.
     
  11. Menorcaman

    Menorcaman Retired Moderator

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    It has been said a number of times over the years. However Acronis Support's latest statement regarding the placement of restored sector is <here>.

    Regards
     
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