I tested Storage Server R2 during the course of a few weeks. I used two HP appliances -- a 1U ProLiant DL100 G2 with 450GB of RAID 5storage and a ProLiant ML310 with 750GB in RAID 5. I installed the ProLiant DL100 in a branch office setting, connecting back to the main office and the ML310 via IPSec VPN. Both appliances were also added to an existing Active Directory and DFS structure. Remember that admins must run the ADPREP utility and extend the schema on their domain before they can take advantage of the newest DFS-related features in R2.

No duplicates, please

One of the more interesting new features in Storage Server R2 is SIS (Single Instance Storage). SIS automatically locates duplicate copies of files on volumes and replaces them with a pointer back to the original file. Duplicate files are identified based on file name, contents, and checksums to ensure all possible duplicates are found. The sparse links used as placeholders look just like the original files when viewed through Explorer, down to date stamps and file size. I like that even though the duplicate file is replaced with a pointer, file and folder permissions are not disrupted.

When enabled for a volume, a background task "crawls" the system, indexing and identifying each file. I did not notice any decrease in server response while the system was performing the initial inspection, and recognition seemed instantaneous as I created duplicate files and folders.

Admins can monitor the space savings obtained by SIS through the MMC-based Storage Management UI. Using SIS on its own servers, Microsoft was able to gain a total space savings of more than 14TB across 269 servers -- my dataset was much smaller, but I saw immediate savings nonetheless. Admins can also filter out specific file types, such as audio, that they don't want to be indexed by SIS.