I have extensively used Microsoft Virtual Server 2005 (graduted to it from Virtual PC) for testing, evaluating and other tasks. In order to test a new product/software I always start off with a clean Microsoft Windows Server 2003 SP1 (Guest OS).
Prepare a clean Windows Server 2003 Sp1 image that you can reuse. Sysprep it and save it. That way new SID’s will be generated everytime you “create” a new guest OS. It is crucial that this base image be optimized for size as well.
These are some tips on optimizing for Virtual PC which can be applied to Virtual Server as well.
* blog.opsan.com – Detailed
* www.hanselman.com – Guidelines
* How to prepare a Virtual Server 2005 virtual hard disk file
After following all the detailed steps, reading the guidelines, precompacting, inspecting and Compacting virtual hard disk my original Guest OS image (Windows 2003 Server SP1 + Microsoft Office Professional + IIS) size was reduced to 2978718208 bytes from 4814174208 bytes (approx 40%), took about 3 hours. My Guest OS images are on an external USB disk. If you dont have 2 seperate disks I highly reccommend getting an USB disk for all your images so that the Host OS and Guest OS dont compete on your system.