Single Instance Store (SIS) in Windows Storage Server R2

The Filing Cabinet : Single Instance Store (SIS) in Windows Storage Server R2

"Single Instance Storage (SIS) in Windows Storage Server 2003 R2 is starting to generate some buzz on other blogs. A blog reader asked us to explain SIS in more detail. Over the next couple days, I’ll publish a series of 4 posts covering SIS basics and design. Many thanks to Claus Joergensen for providing this information.

SIS is a storage feature available on Microsoft® Windows Storage Server™ 2003 R2.  Single Instance Storage (SIS) recovers disk space by reducing the amount of redundant data stored on a volume by identifying identical files, storing only a single copy of the file in the SIS common store and replacing the files with links to the file in the SIS common store. Consider the following scenario:

1. Two users receive the same e-mail with an attachment. They both save the attachment to their home folder. SIS runs in the background and detects the two identical files on the volume and moves one of the copies into the SIS common store and replaces both files with a link to the file in the SIS common store.

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SIS provides the following benefits:

• SIS reduces disk space consumption by eliminating duplicate files--our own IT department (MS-IT) saved 14 TB (40%) on servers hosting MS products
• SIS is a set it and forget it feature. It does not require daily maintenance.
• SIS is transparent to the end users and applications
• SIS provides a backup API that allows backup apps to determine if file is SIS’d and only back up the file once (most major Backup application vendors support SIS)

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Interesting…