Re: How to increase RAM memory to guest OS?

Assuming you run Windows 2008 R2, you should be ok with:

1. File server - for about 20 people - 4GB
2. Web server - for about 30 people - 4GB
3. Oracle server - for about 15 people - 8-12GB (difficult to guess)
4. Domain server - for about 20 people - 4GB

You can certainly assign more memory to each of the guests, but they will most likely not use it anyway.

André