Compressed to Uncompressed Snapshot

Discussion in 'FirstDefense-ISR Forum' started by TonyW, Oct 27, 2006.

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  1. TonyW

    TonyW Registered Member

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    I don't know if anyone else has noticed, but if you copy/update a compressed snapshot to an uncompressed snapshot some files become uncompressed that were compressed before.

    For example, under the Windows folder you see all the Uninstall folders when not hidden, and they have always been highlighted in blue. After a copy/update exercise as I described, they are highlighted in black. I did see 'Setting attributes...' during this process.

    Just wondering if this is Ok.
     
  2. ErikAlbert

    ErikAlbert Registered Member

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    I don't have any experience with compressed snapshots and I didn't install the upgrade yet. I'm going to wait until I reinstall my computer from scratch.

    Nevertheless, I'm not surprised that when you have a mixture of not-compressed and compressed snapshots, that weird things can occur.

    If you work with a mixture you have 4 possible combinations in theory :
    1. FROM not-compressed snapshot TO not-compressed snapshot = normal
    2. FROM compressed snapshot TO compressed snapshot = normal.
    3. FROM not-compressed snapshot TO compressed snapshot = ?
    4. FROM compressed snapshot TO not-compressed snapshot = ?

    The last two combinations aren't normal.
    The crucial question : Is that a problem or not, only Raxco can give you the answer.
     
  3. TonyW

    TonyW Registered Member

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    Once you create a compressed snapshot, it stays compressed so any updating of it from the not-compressed snapshot remains compressed and vice versa.

    The anomaly is in compression attributes for some files, which I discovered by accident.
     
  4. ErikAlbert

    ErikAlbert Registered Member

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    Only Raxco can give you the answer. My assumption is that once a snapshot is compressed, all objects in that snapshot are compressed.
    Maybe FDISR makes exceptions for certain file-types or the compression doesn't work properly or it doesn't matter.
    I thought that FDISR didn't take care of the compression, it seems to use an existing compression method of Windows for NTFS.
     
  5. TonyW

    TonyW Registered Member

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  6. ErikAlbert

    ErikAlbert Registered Member

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  7. wilbertnl

    wilbertnl Registered Member

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    It doesn't have an effect on the functioning of your system, if that's what you ask.
    Your uncompressed snapshot will take some more space, because by default compressed folders/files became uncompressed.

    Looks like FD-ISR has no reference of which folders are compressed by default by Microsoft or other companies.
     
  8. TonyW

    TonyW Registered Member

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    To illustrate what I mean I attach a screenshot of part of my Windows folder in my Primary Snapshot, which is uncompressed.

    Before I copied/updated the Primary to a Test Snapshot in compressed mode, all those hidden $NtUninstall folders were in blue, presumably because they were compressed due to the NTFS compression feature of Windows.

    They remain in blue in the Test Snapshot.

    However, when I copied/updated the Primary with the Test, they show up as black and look as if they have been uncompressed.

    It works the other way too as I found a file I moved to another folder in the Test Snapshot, and that is now showing up in blue because it is compressed in the Primary Snapshot. I merely unticked the 'compress contents' under Advanced Attributes, and it's now in black.

    But I'm not going through all those $NtUninstall folders to re-attribute them back to blue, which is what they were originally.
     

    Attached Files:

  9. King FN Kong

    King FN Kong Registered Member

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    The readme.txt has some notes on it

    btw imaging a partition with compressed snapshots gives me larger image files.
     
  10. wilbertnl

    wilbertnl Registered Member

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    What would happen in the following scenario:
    Code:
    In the decompressed snapshot delete all the hidden $NT* folders.
    Switch to a regular snapshot and copy/update to the decompressed snapshot.
    Check that the $NT* folders are compressed.
    
     
  11. TonyW

    TonyW Registered Member

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    I deleted all those blue hidden $NT* folders in my compressed snapshot. I booted back to my uncompressed snapshot, and copy/updated to the compressed snapshot. Booting back into the compressed snapshot, I find all the hidden folders back again all highlighted in blue.
     
  12. wilbertnl

    wilbertnl Registered Member

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    ét voila!
     
  13. TonyW

    TonyW Registered Member

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    Yes, but the point is it looks like that if you copy/update the other way those files become uncompressed, which is not what I was expecting. I thought those MS files/folders would remain compressed either way.
     
  14. cthorpe

    cthorpe Registered Member

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    When you copy a compressed snapshot to an uncompressed snapshot, ISR uncompresses all the files. I assume that ISR doesn't remember that those particular folders were compressed originally and uncompresses them along with all the rest of the data.

    C
     
  15. ErikAlbert

    ErikAlbert Registered Member

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    As far I understand you can't copy/update a compressed snapshot to an uncompressed snapshot. The destination snapshot in this case would be compressed too.

    You can copy/update a compressed snapshot to an archived snapshot and that archived snapshot will be uncompressed, but that isn't the same operation.
     
  16. TonyW

    TonyW Registered Member

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    You can copy/update a compressed snapshot to an uncompressed snapshot - I demonstrated that earlier in this thread - all that happens is the uncompressed snapshot remains uncompressed, and it seems that any files that were compressed in the compressed snapshot, like those $NT* folders I was talking about, become uncompressed in the uncompressed snapshot.
     
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