Finds a file by user name (if Disk Quotas are enabled), queries allocated ranges for a file, sets a file's short name, sets a file's valid data length, sets zero data for a file, or creates a new file.
For examples of how to use this command, see Examples.
Syntax
fsutil file [createnew] <FileName> <Length> fsutil file [findbysid] <UserName> <Directory> fsutil file [queryallocranges] offset=<Offset> length=<Length> <FileName> fsutil file [setshortname] <FileName> <ShortName> fsutil file [setvaliddata] <FileName> <DataLength> fsutil file [setzerodata] offset=<Offset> length=<Length> <FileName>
Parameters
| Parameter | Description |
|---|---|
|
createnew |
Creates a file of the specified name and size, with content that consists of zeroes. |
|
<FileName> |
Specifies the full path to the file including the file name and extension, for example C:\documents\filename.txt. |
|
<Length> |
Specifies the file's valid data length. |
|
findbysid |
Finds files that belong to a specified user on NTFS volumes where Disk Quotas are enabled. |
|
<UserName> |
Specifies the user's user name or logon name. |
|
<Directory> |
Specifies the full path to the directory, for example C:\users. |
|
queryallocranges |
Queries the allocated ranges for a file on an NTFS volume. Useful for determining whether a file has sparse regions. |
|
offset=<Offset> |
Specifies the start of the range that should be set to zeroes. |
|
length=<Length> |
Specifies the length of the range (in bytes). |
|
setshortname |
Sets the short name (8.3 character-length file name) for a file on an NTFS volume. |
|
<ShortName> |
Specifies the file's short name. |
|
setvaliddata |
Sets the valid data length for a file on an NTFS volume. |
|
<DataLength> |
Specifies the length of the file in bytes. |
|
setzerodata |
Sets a range (specified by Offset and Length) of the file to zeroes, which empties the file. If the file is a sparse file, the underlying allocation units are decommitted. |
Remarks
- In NTFS, there are two important concepts of file length: the
end-of-file (EOF) marker and the Valid Data Length (VDL). The EOF
indicates the actual length of the file. The VDL identifies the
length of valid data on disk. Any reads between VDL and EOF
automatically return 0 to preserve the C2 object reuse
requirement.
- The setvaliddata parameter is only available for
administrators because it requires the Perform volume maintenance
tasks (SeManageVolumePrivilege) privilege. This feature is only
required for advanced multimedia and system area network scenarios.
The setvaliddata parameter must be a positive value that is
greater than the current VDL, but less than the current file
size.
It is useful for programs to set a VDL when:
- Writing raw clusters directly to disk through a hardware
channel. This allows the program to inform the file system that
this range contains valid data that can be returned to the
user.
- Creating large files when performance is an issue. This avoids
the time it takes to fill the file with zeroes when the file is
created or extended.
- Writing raw clusters directly to disk through a hardware
channel. This allows the program to inform the file system that
this range contains valid data that can be returned to the
user.
Examples
To find files that are owned by scottb on drive C, type:
fsutil file findbysid scottb c:\users
To query the allocated ranges for a file on an NTFS volume, type:
fsutil file queryallocranges offset=1024 length=64 c:\temp\sample.txt
To set the short name for the file Longfilename.txt on drive C to Longfile.txt, type:
fsutil file setshortname c:\longfilename.txt longfile.txt
To set the valid data length to 4096 bytes for a file named Testfile.txt on an NTFS volume, type:
fsutil file setvaliddata c:\testfile.txt 4096
To set a range of a file on an NTFS volume to zeros to empty it, type:
fsutil file setzerodata offset=100 length=150 c:\temp\sample.txt