Fsutil: usn

Typically used by support professionals. Manages the update sequence number (USN) change journal, which provides a persistent log of all changes made to files on the volume. As files, directories, and other NTFS objects are added, deleted, and modified, NTFS enters records into the USN change journal, one for each volume on the computer. Each record indicates the type of change and the object changed. New records are appended to the end of the stream.

Programs can consult the USN change journal to determine all the modifications made to a set of files. The USN change journal is much more efficient than checking time stamps or registering for file notifications. The USN change journal is enabled and used by the Indexing Service, File Replication Service (FRS), Remote Installation Service (RIS), and Remote Storage.

Syntax

fsutil usn [createjournal] MaximumSize AllocationDelta VolumePathname

fsutil usn [deletejournal] flags VolumePathname

fsutil usn [enumdata] FileRef LowUsn HighUsn PathName

fsutil usn [queryjournal] VolumePathname

fsutil usn [readdata] PathName

Parameters

createjournal : Creates a USN change journal.

m=MaximumSize : Specifies the maximum size, in bytes, that NTFS allocates for the change journal.

a=AllocationDelta : Specifies the size, in bytes, of memory allocation that is added to the end and removed from the beginning of the change journal.

VolumePathname : Specifies the drive letter (followed by a colon), mount point, or volume name.

deletejournal : Deletes or disables an active USN change journal.

flags : /D: Disables an active USN change journal, and returns I/O control while the change journal is being disabled.

VolumePathname : Specifies the drive letter (followed by a colon), mount point, or volume name.

enumdata : Enumerates and lists the change journal entries between two specified boundaries.

FileRef : Ordinal position within the files on the volume at which the enumeration is to begin.

LowUsn : Lower boundary of the range of USN values used to filter which records are returned. Only records whose last change journal USN is between or equal to the LowUsn and HighUsn member values are returned.

HighUsn : Upper boundary of the range of USN values used to filter which files are returned.

PathName : Specifies the drive letter (followed by a colon), mount point, or volume name.

queryjournal : Queries a volume's USN data to gather information about the current change journal, its records, and its capacity.

volume pathname : Specifies the drive letter (followed by a colon), mount point, or volume name.

readdata : Read the USN data for a file.

PathName : Specifies the drive letter (followed by a colon), mount point, or volume name.

Remarks

Using createjournal 

If a change journal already exists on a volume, the createjournal parameter updates the change journal's MaximumSize and AllocationDelta parameters. This allows you to expand the number of records that an active journal maintains without having to disable it. If you specify zero for MaximumSize and AllocationDelta, the system chooses a default value based on the volume size.

Using m=MaximumSize 

The change journal can grow larger than this target value, but the change journal is truncated at the next NTFS checkpoint to less than this value. NTFS examines the change journal and trims it when its size exceeds the value of MaximumSize plus the value of AllocationDelta. At NTFS checkpoints, the operating system writes records to the NTFS log file that allow NTFS to determine what processing is required to recover from a failure.

Using a=AllocationDelta 

The change journal can grow to more than the sum of the values of MaximumSize and AllocationDelta before being trimmed.

Using deletejournal 

Deleting or disabling an active journal is very time consuming, because the system must access all the records in the master file table (MFT) and set the last USN attribute to zero. This process can take several minutes, and can continue after the system restarts, if necessary. During this process, the change journal is not considered active, nor is it disabled. While the system is disabling the journal, it cannot be accessed, and all journal operations return errors. You should use extreme care when disabling an active journal, because it adversely affects other applications using the journal.

Examples

To create a USN change journal on drive C, type:

fsutil usn createjournal m=1000 a=100 C:

To delete an active USN change journal on drive C, type:

fsutil usn deletejournal /D C:

To enumerate and list the change journal entries between two specified boundaries on drive C, type:

fsutil usn enumdata 1 0 1 C:

To query USN data for a volume on drive C, type:

fsutil usn queryjournal C:

To read the USN data for a file in the temp folder on drive C, type:

fsutil usn readdata C:\Temp\sample.txt

Fsutil

Fsutil: behavior

Fsutil: dirty

Fsutil: file

Fsutil: fsinfo

Fsutil: hardlink

Fsutil: objectid

Fsutil: quota

Fsutil: reparsepoint

Fsutil: sparse

Fsutil: volume

Command-line reference A-Z



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