Single Instance Storage

Windows Storage Server 2008 ships with Single Instance Storage (SIS) — this will enable Storage Server to save space because it will save duplicate files only once. SIS will check all the files on the hard disk 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 physically as a new file — no files or content gets lost.

Enable SIS on a drive:

sisadmin /i D:

Note: SIS cannot be enabled on the system drive!

Activate SIS on the drive:

sisadmin /e D:

Start checking for duplicate files:

sisadmin /r

List files stored only once:

sisadmin /l D:

Uninstall SIS (converts all links back to files):

sisadmin /u D: