Resource Cost of Network Interfaces

[rttrsa]

I've an odd sort of meta-question: when building VMs, is there an appreciable cost in terms of compute and network resources when adding extra network interfaces? In other words, all else being equal, does a VM with 12 network adapters use significantly more resources than a VM with 1? For a workload/VM OS consideration, let's say nested ESXi running very minimal child VMs, because that's the precise context that raised this question in my mind.

[nancyz]

In other words, all else being equal, does a VM with 12 network adapters use significantly more resources than a VM with 1?For a workload/VM OS consideration, let's say nested ESXi running very minimal child VMs, because that's the precise context that raised this question in my mind.

It depends on how you allocate your VM network adapters. If you nested ESXi running in NAT, all VM will send its traffic using your first active adapter on your Mac (you could know which is the first active adapter via System Preferences->Network, all use netstat command on your Mac); if you are using Bridged for your ESXi VMs, the traffic for ESXi VMs will send through the adapter    which your ESXi VM is bridged to .