I have tried searching for an answer to this, but to no avail.
What is considered a best practice in a scenario, where you would need to add a 2nd IP address, from a different address range to a machine? Network ranges for example are:
Range 1 - public IP.
Range 2 - private IP.
The ranges have routing in between them.
And the methods are:
Option A: You already have 1 NIC added, using IP from Range 1, so you just add the 2nd IP address to it, aliasing it.
Option B: You add a 2nd NIC to the machine, and bind the 2nd IP address to it.
I have been left under the impression, that Option B is considered a better option, but no actual information on why so.
PS: We are assuming virtual environment, so physical NICs/slots and such are not involved.
It all really depends on the speed that you need for each link and the amount of configuration you want to go into doing something like this.
Assuming that your NICs are 1Gbps and you put 2 IPs on that one NIC, then the global maximum speed you can reach will be 1Gbps. Obviously if you have two NICs then you will have 2Gbps total maximum speed. (1-1 each)
While configuration of two IPs on one NIC is possible, it generally is more advisable to try to separate networks with NICs whenever possible.
Option B is definitely a better option to go.
The above mentioned part is mainly meant for physical configuration. For virtual environments the speed will still be limited by the interface speed of the card, but assuming that you won't be pushing too much traffic over these interfaces I'd opt for 2 virtual NICs.