A valuable feature of WSS2008 is its Single Instance Storage (SIS), which was introduced in WSS2003 R2 and delivers data deduplication. However, although this may be a very hot topic at the moment be aware that Microsoft's implementation operates only at the file level and not the block level and doesn't support system and boot volumes or remote drives.
The Groveler service scans NTFS volumes designated for SIS operations looking for duplicate files. It moves them to the hidden Common File Store and replaces them with links. New SIS features in this version are support for clusters, an increase from six SIS volumes per server to 20 and the ability to remove SIS from a volume.
During share creation you can apply an extensive range of quotas and file screening controls.
SIS is easy enough to configure, although it's disappointing that you have to use the command line as it still has no GUI. You just decide which volumes to run SIS on and leave the Groveler service to get on with this in the background.
To test SIS we created a couple of shared folders on one test volume and copied the same 4GB data sample to each one. We started SIS on the volume and after less than an hour the amount of used storage on the volume had dropped from 8GB down to only 3.5GB, showing that there was also file duplication within our test sample.
SIS can make big savings on storage but it still has to be run from the command prompt.
A wizard helps with iSCSI target creation where you select a volume, provide a meaningful target name and assign logged in initiators to it. Within the target you create virtual disks, which require an absolute path name for the VHD file and a size.
To test IP SAN performance we used a Boston dual Xeon 5160 server running Windows Server 2003 R2 and logged on to the Igloo using Microsoft's iSCSI initiator v2.08. The Iometer utility reported a fast 106MB/sec raw read speed, which isn't far off tops for a Gigabit connection.
