Hardware: Intel® Core™ i7-920, 12 GB DDR3 RAM, 2 x 1500 GB SATA-II HDD (no SoftRaid because Proxmox developers don't support softraid and they are sure you'll run into problems)
Software: Proxmox VE with KVM and OpenVZ support and debian everywhere
I want to run multiple Linux VMs on this server. One for a firewall (I want to try pfSense), one for MySQL, one VM for nginx (my stuff) and ~2 VMs with nginx for other people's web sites.
I don't think that pfSense will run in an OpenVZ environment but it should run in KVM.
The question is if I should setup the other VMs using KVM or OpenVZ. In OpenVZ they should have less overhead for the OS itself but I don't know about the performance. I heard that KVM is more stable but needs more RAM and CPU.
I found this diagram showing a OpenVZ setup on the same hardware I'm using. This guy uses an own VM for each and every website which is running on his server. I can't think of any advantage why he's using so many VMs.
Is there a way to give the VMs "dynamic" RAM in OpenVZ or KVM? I mean so they can take as much memory as available and not as much as I dedicated to them.