First, those web apps like to use all CPU power available. I mean with a few users using them, you need to slow them down to keep the server running. So I use "renice 20
Next you will want to make the swap partition big enough. A REAL Studio app with a leak will go until 4 GB until it crashes. If the server does not crash before. So I'm now using 10 GB for the swap partition. But currently we don't need it. 7 web apps are running and total memory usage is just 300 MB (including the LInux OS and other system applications).