I am building a small setup of ESX5 servers. There will be different apps running for different companies on them. Each company has a VM that has one Internet facing vNIC and one vNIC facing to this company's private virtual network (backend). The backend networks are for separate web server and database VMs.
The question is: would it be performance and/or security wise better to create a separate virtual switch for each company or just use VLAN tags? I mean if all the private networks are load-wise fully utilized, would it make a difference if they used separate virtual switches?