I am setting up a new network which customers will host their applications on. It needs to be able to scale out to a few hundred servers and each server will have several VMs on it. Right now in my test environment, after the telco router, we are using a Linux router/firewall which is then connected to a Layer 2 switch. Could be a layer 3 in the future. I need to track total bandwidth per VM for each machine, and I need to do it in a way that it is not part of the VM. Each VM will have a private class ip address which is Natted by the gateway, or we may eventually run more than firewall/reverse proxy off a layer 3 switch.
So my thinking is that I can do it off of a promiscuous port on the switches, or at the gateway firewall. I would like to have an out of the box solution, preferably open source. Does anyone have suggestions on the easiest way to set this up, and the easiest tool to use. I have looked at the web sites for Nagios, Zenoss, Zabbix, ntops on the firewall, etc. It is hard to ascertain just from the web sites if they do exactly this or not. Obviously, performance is also somewhat key here. Anything running on the gateway should not drag it down doing traffic accounting.
Thanks for any thoughts.