I am new to the OpenFire side of Spark. I am setting up our first permanent OpenFire server. I set up a testing server to become acclimated with OpenFire and it is working great. Now the task is to get ready for deployment for 400 users. If I were to install this on a Windows 2012 or 2016 virtual server, what capacities of RAM and hard drive space are required for optimal end user experience? How many processors and cores would be suggested? Also, would using the DB in the software or an external DB produce better results, in general?