Can you help me with my capacity planning?
My query is regarding how to specify a physical host, to serve virtual machines, and what 'rules of thumb' you would use regarding how many virtual instances could reside on a physical host. I appreciate that this can vary greatly depending upon the server instance, and the workload, and these are easy to understand in isolation, but this changes once you start putting several VMs on a box, they compete for resources, and you need to think about the overall performance of the server, rather than the individual VM.
I've read on another site as rough guide to have roughly 2-4GB RAM per core, 2 cores per VM. So if you had 8 Cores, 32GB RAM you'd be looking at running 4 WS2008R2 full installs comfortably. Disk IOPs important too, so should you be looking at a nice fast RAID array? Finally presumably you'd want two NICs minimum?