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Wanting to do differential file sync using something like VSS (or other) RRS feed

  • Question

  • I'm wanting to backup files based on changes in a similar way to how VSS (VolumeShadowService) does.  That is, I want to backup the original file, then when it changes, just backup the blocks that changed, not the entire file again.  That is, if I have a 200 meg file and only a couple dozen blocks change, I don't want to re-replicated the entire file like happens with the build in file provider.

    How can I do this with Sync Framework?


    Peter Kellner http://peterkellner.net Microsoft MVP • ASPInsider
    Sunday, January 31, 2010 7:50 PM

Answers

  • Unfortunately this is not a supported scenario with the file sync provider.
    If you want to implement this yourselves, then you would need to break open the file and compare block by block and then overwrite. But then you will face the challenge of just inserting the changes and may end up probably writing all blocks from where you detect differences. And at this point, maybe it is better to use the current behavior of file sync provider and have less headache :)


    This posting is provided AS IS with no warranties, and confers no rights
    Friday, February 5, 2010 7:13 AM

All replies

  • ping..
    Peter Kellner http://peterkellner.net Microsoft MVP • ASPInsider
    Thursday, February 4, 2010 2:10 PM
  • Unfortunately this is not a supported scenario with the file sync provider.
    If you want to implement this yourselves, then you would need to break open the file and compare block by block and then overwrite. But then you will face the challenge of just inserting the changes and may end up probably writing all blocks from where you detect differences. And at this point, maybe it is better to use the current behavior of file sync provider and have less headache :)


    This posting is provided AS IS with no warranties, and confers no rights
    Friday, February 5, 2010 7:13 AM