Windows Storage Server 2008 ships with Single Instance Storage – this will enable Storage Server to save space because it will save duplicate files only once. SIS will check all the files on the harddisk for duplicate ones – if they are found it will be saved only once in the Common Store. All files will only link to the physical file in the common store. If one of the duplicate files changes it will be automatically saved phyiscally as new files – no files or content gets lost.

To enable SIS use the following command:

sisadmin /i D:

Note: SIS cannot be enabled on the system drive!

To enable SIS on the drive enter the following command:

sisadmin /e D:

To start checking for duplicate files run the following command:

sisadmin /r

To list the current files which are stored only once use the following command:

sisadmin /l D:

To uninstall SIS use the following command – this will convert all links back to files!

sisadmin /u D:

Here is a video demonstrating SIS: