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USN_TRACK_MODIFIED_RANGES structure (winioctl.h)

  • Article

Contains information on range tracking parameters for an update sequence number (USN) change journal using the FSCTL_USN_TRACK_MODIFIED_RANGES control code.

Syntax

typedef struct {
  DWORD     Flags;
  DWORD     Unused;
  DWORDLONG ChunkSize;
  LONGLONG  FileSizeThreshold;
} USN_TRACK_MODIFIED_RANGES, *PUSN_TRACK_MODIFIED_RANGES;

Members

Flags

Indicates enabling range tracking.

Value Description
FLAG_USN_TRACK_MODIFIED_RANGES_ENABLE 0x00000001 This flag is mandatory with FSCTL_USN_TRACK_MODIFIED_RANGES and is used to enable range tracking on the volume.

Unused

Reserved.

ChunkSize

Chunk size for tracking ranges. A single byte modification will be reflected as the whole chunk being modified.

FileSizeThreshold

File size threshold to start outputting USN_RECORD_V4 structure record(s) for modified file, i.e. if the modified file size is less than this threshold, then no USN_RECORD_V4 record will be output.

Remarks

Once range tracking is enabled for a given volume it cannot be disabled except by deleting the USN Journal and recreating it.

Requirements

Requirement Value
Minimum supported client Windows 8.1 [desktop apps only]
Minimum supported server Windows Server 2012 R2 [desktop apps only]
Header winioctl.h (include Windows.h)

See also

FSCTL_USN_TRACK_MODIFIED_RANGES