How to create and manipulate NTFS junction points (205524)

SUMMARY

You can surpass the 26 drive letter limitation by using NTFS junction points. By using junction points, you can graft a target folder onto another NTFS folder or "mount" a volume onto an NTFS junction point. Junction points are transparent to programs.

Preview Tools for NTFS Junction Points

Microsoft offers three utilities for creating and manipulating NTFS junction points:

Linkd.exe

Grafts any target folder onto a Windows 2000 version of NTFS folder
Displays the target of an NTFS junction point
Deletes NTFS junction points that are created with Linkd.exe
Location: Microsoft Windows 2000 Resource Kit

Mountvol.exe

Grafts the root folder of a local volume onto a Windows 2000 version of NTFS folder (or "mounts" the volume)
Displays the target of an NTFS junction point that is used to mount a volume
Lists the local file system volumes that are available for use
Deletes the volume mount points that are created with mountvol.exe
Location: Windows 2000 CD-ROM in the I386 folder

Delrp.exe

Deletes NTFS junction points
Also deletes other types of reparse points, which are the entities that underlie junction points
Aimed primarily at developers who create reparse points
Location: Microsoft Windows 2000 Resource Kit

MORE INFORMATION

Sample Usage

To create a junction point to your desktop:
1. At a command prompt, type linkd mydesktop user profile\desktop (where user profile is the name of the user profile).
2. Type dir mydesktop to display the contents of your desktop.
To list the available volumes on your system, at a command prompt, type mountvol.
```
\\?\Volume{e2464851-8089-11d2-8803-806d6172696f}\ C:\ 

\\?\Volume{e2464852-8089-11d2-8803-806d6172696f}\ D:\ 

\\?\Volume{e2464850-8089-11d2-8803-806d6172696f}\ R:\ 
					
```
NOTE: The string after "Volume" is the GUID that is used to identify a unique volume even if the drive letter changes.
To mount your CD-ROM onto an NTFS junction point:
1. At a command prompt, type md cd.
2. Type mountvol cd \\?\Volume{e2464850-8089-11d2-8803-806d6172696f}\.
3. Type dir cd to display the contents of your CD-ROM.
To mount another volume onto an NTFS junction point on your system drive:
1. At a command prompt, type md ddrive.
2. Type mountvol ddrive \\?\Volume{e2464852-8089-11d2-8803-806d6172696f}\
3. Type dir ddrive to displays the contents of drive D.
NOTE: When you display the contents of a folder by using the "dir" command, NTFS junction points are indicated by {Junction}.
To delete junction points:
- To delete the mydesktop junction point, at a command prompt, type linkd mydesktop /d or Delrp mydesktop.
- To delete the CD mount point, at a command prompt, type mountvol \\?\Volume{e2464850-8089-11d2-8803-806d6172696f}\ /d.
- To delete the ddrive mount point, at a command prompt, type mountvol \\?\Volume{e2464852-8089-11d2-8803-806d6172696f}\ /d.

Usage Recommendations

NOTE: Microsoft recommends that you follow these recommendations closely when you use junction points:

Use NTFS ACLs to protect junction points from inadvertent deletion.
Use NTFS ACLs to protect files and directories that are targeted by junction points from inadvertent deletion or other file system operations.
Never delete a junction point by using Explorer, a del /s command, or other file system utilities that walk recursively into directory trees. These utilities affect the target directory and all subdirectories.
Use caution when you apply ACLs or change file compression in a directory tree that includes NTFS junction points.
Do not create namespace cycles with NTFS or DFS junction points.
Put all your junction points in a secure location in a namespace where you can test them out in safety, and where other users will not mistakenly delete them or walk through them.

Feature Comparison to DFS

NTFS junction points are similar to the junction points in DFS because both are tools that are used to graft storage namespaces together. However, DFS junction points typically have more features than NTFS junction points. The following table lists some of the differences between DFS and NTFS junction points.

Feature	DFS Junction Points	NTFS Junction Points
Junction point origin	Local network share	Local NTFS directory
Junction point target	Any network share	Any valid Windows 2000 local path
Recoverable	Yes	Yes (ChkDsk)
Persistable/portable state	Yes (Save as File)	Yes (explicit/copy/move/backup)
Multi-targeting	Yes	No
API	Yes	Yes
Graphical Tools	Yes	Minimal
Availability	NT Server 4.0 and Later	Windows 2000 w/NTFS

For additional information about the support of NTFS junction points on a cluster, click the following article number to view the article in the Microsoft Knowledge Base:

262797 Reparse point support in Windows 2000-based clusters