Hack 64 Tune RIS

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If you can't afford the resources to run a dedicated RIS server for your environment, you can use RIS on a dual-purpose server?as long as you tune it carefully.

Let's talk about fine-tuning RIS if there are other folders on the volume (i.e., other than the OS images used by RIS) and how to handle the restoration of the volume managed by SIS. To do this, we will have to dig deeper into how SIS works.

By storing a only a single copy of data in a folder on the volume, SIS helps reduce the amount of disk space that contains the OS images used by RIS. When SIS Groveler starts, it searches the root of each NTFS volume to see if it contains the SIS folder named SIS Common Store and a file called MaxIndex within that directory. If the Groveler finds this folder and file and if the SIS filter driver is installed on the system, the Groveler knows to search for and consolidate duplicate files on the volume.

SIS uses the same technology as the Indexing Service, and it is designed to not consume CPU time when the system requires it for other functions. The exception is when disk space drops below a specific value; in this case, the Groveler will increase CPU usage regardless of system activity, to ensure that disk space is not entirely consumed.

To effectively manage duplicate files that it detects when scanning a volume, SIS places the data in the SIS common store and the original files are changed to reparse points with referrals to the <GUID>.sis file. When the application tries to access the original file, the filesystem redirects any file I/O to the <GUID>.sis file in SIS Common Store. For example, if SIS detects the file net1.ex_ in both the RIS\SETUP\ENGLISH\IMAGES\WindowsXP.Pro\i386 and \SETUP\ENGLISH\IMAGES\WindowsXP.Pro.SP1\i386 folders, it places the duplicate file in the SIS common store and the references of those files are changed to reparse points with referrals (or links) to the <GUID>.sis file.

Now, let's say you have a dual-purpose Windows 2000 Server that is both a file-sharing server and a RIS server. The volume that houses the RIS OS images also has the file shares. When the Groveler service performs its daily ritual, it will scan through all folders on that volume. To improve efficiency of SIS and restore SIS links or reparse points, you can exclude certain directories from the Groveler scan.

To exclude a directory on a single volume, modify the Grovel.ini file located in the SIS Common Store folder (this folder is hidden by default). First, you will need to modify the NTFS permissions of the folder, because only SYSTEM has full control rights by default. Then, under the [Excluded Paths] section, add the required entry?for example, Directory 1 Folder = \Folder1. Note that the value to the left of the equals sign can be of any designation you wish. Now, stop and restart the Single Instance Storage service and you're done.

To exclude a directory on all volumes, open Registry Editor and add an entry to the following key:

HKLM\Software\Microsoft\Windows NT\CurrentVersion\Groveler\ExcludedPaths

The value can have any name?for example, Folder 1 Directory REG_SZ \Folder1. Again, after you've done this, stop and restart the Single Instance Storage service.

In an enterprise environment, you should have a dedicated Windows 2000 server or servers to provide RIS images, depending on how many desktops you are supporting. In a smaller environment, it is reasonable to have a multipurpose server provide RIS, as long as it has the resources to support the additional overhead.

Finally, to restore a volume that is managed by SIS, follow the instructions in KB Article 263027 (http://support.microsoft.com/default.aspx?scid=kb;en-us;263027). How you handle a restore depends on the failure you are faced with, such as failed disk drives, controllers, or the like. Follow this article carefully to ensure you are not faced with data corruption because of the linked files managed by SIS!

For more helpful information on using RIS to deploy Windows, see my column at myITforum.com (http://www.myitforum.com).

?Matt Goedtel