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DeviceIoControl(FSCTL_USN_TRACK_MODIFIED_RANGES) does not work to change @ChunkSize and @FileSizeThreshold RRS feed

  • Question

  • Hi,

    I'm trying to enable the range tracking feature on a NTFS volume on Windows 10 desktop. The range tracking is enabled. But the chuck-size and the file-size-threshold can never be changed. They are always 16384 and 1048576, respectively.

    For example:

    C:\WINDOWS\system32>fsutil usn queryjournal e:
    Usn Journal ID   : 0x01d4606e19f40518
    First Usn        : 0x0000000000000000
    Next Usn         : 0x0000000000000668
    Lowest Valid Usn : 0x0000000000000000
    Max Usn          : 0x7fffffffffff0000
    Maximum Size     : 0x0000000000400000
    Allocation Delta : 0x0000000000100000
    Minimum record version supported : 2
    Maximum record version supported : 4
    Write range tracking: Enabled
    Write range tracking chunk size: 16384
    Write range tracking file size threshold: 1048576

    C:\WINDOWS\system32>fsutil usn enablerangetracking c=1024 s=2048 e:

    C:\WINDOWS\system32>fsutil usn queryjournal e:
    Usn Journal ID   : 0x01d4606e19f40518
    First Usn        : 0x0000000000000000
    Next Usn         : 0x0000000000000668
    Lowest Valid Usn : 0x0000000000000000
    Max Usn          : 0x7fffffffffff0000
    Maximum Size     : 0x0000000000400000
    Allocation Delta : 0x0000000000100000
    Minimum record version supported : 2
    Maximum record version supported : 4
    Write range tracking: Enabled
    Write range tracking chunk size: 16384
    Write range tracking file size threshold: 1048576

    I did try w/ other numbers, but it turns out that they are fixed to 16384, 1048575. No error is returned.

    Also, I tried DeviceIoControl(FSCTL_USN_TRACK_MODIFIED_RANGES) which succeeds w/ error. But the @ChunkSize and @FileSizeThreshold just don't take effect.

    Is this a known issue?

    Thanks,
    Jing

    Wednesday, October 10, 2018 2:18 PM