Hi, this is Mark Aggar, Senior Product Planner for Windows Server.  Although my focus is now moving onto post-Longhorn projects, I’m still heavily involved with Longhorn itself (for those that care, I also did the planning for Windows Server 2003 R2).

Now that we’ve got the formalities out of the way, I wanted to address a topic that I hear about a lot from folks inside and outside of the Server organization – “server roles”.  More specifically, folks have been hearing that the Windows Server “Longhorn” (WSL) is going to be a lot more “modular”, with a “focus on roles”.  So what does that mean exactly?

Case in point, I received a press inquiry the other day that asked “What is the difference between Longhorn and Win 03 Server in terms of modularity?  Win O3 also can be set up for specific tasks. What sort of improvement/change does LHorn represent?

Here’s the answer I gave:

“We are making the server ‘compose-able’ at three different levels in Windows Server “Longhorn”.  The first is to allow the server to be installed in a mode where it doesn’t have a GUI or any of the other stuff required to run the GUI.  This reduces the server footprint quite dramatically, but only a handful of server roles can run on the box in this mode and there’s definitely a tradeoff from an administration POV. Secondly we’re ensuring that for the most part only the bits that are needed to run the box are in the Windows directory. We do this to some degree today with Windows Server 2003 (for instance IIS needs isn’t on the box after you’ve finished with setup), but we’re greatly expanding the scope of this for Longhorn. Lastly, some of the roles themselves will be more compose-able.  The best example I can give you today is IIS 7.0, which has been re-factored into lots of ‘modules’ that can be optionally installed and even replaced by third party modules.”

So why is this important?  Well, many IT Pros tell us that less is more for a variety of reasons.  I believe this all boils down to reduced maintenance (less bits on the box to have to deal with), but there are side benefits with regard to security (less chance of something being on the box you didn’t know about) and reliability (less stuff to go wrong which might break something else). There’s also potentially a performance benefit, especially in terms of the amount of memory required for a particular OS instance, which can help make virtualization more efficient (more instances per box).

This is definitely a long term effort for Microsoft – future major OS releases will be re-factored even more so, with the goal of running more server roles on a reduced footprint and breaking dependencies even further.

If you have feedback on this, I’d love to hear it.

-Mark Aggar