How can I measure the performance penalty of a network adapter that is configured with 2 IP
addresses per eth0 ?
The network card has 2 physical interfaces (ports): eth0 and eth1 with only eth0 enabled and
configured with 2 IP's: one for host (Ubuntu 8.04) and one for virtual machine (VirtualBox 4.x bridged mode).
If I configure the second IP to eth1 and set the virtual machine to bridge on it will it have any
impact ?
Best Answer
If you want to measure the performance penalty, you would need to create an appropriate client/server setup. and run transfer tests to your liking.
But there would not be a performance penalty for additional IP addresses. There might be an increase in CPU usage if you have more than one MAC address configured or run the interface in promiscuous mode (likely, if you have a bridging setup) as the host would need to evaluate the entire traffic that is received on eth0, not being able to use the NIC's filtering on broadcasts and the "own" MAC address. However, the impact would be negligible in a correctly configured switched network - the switch will mostly forward only relevant traffic to the interface.