What's the Point of Standby NICs?

[samcatoe]

I can't think of a situation where you would ever want to use a standby NIC. Whether you etherchannel the ports or use route based on originating port ID, all of the VMs will still connect to the other active NICs if their physical NIC fails. It seems like a waste of a port to have one on standby when you can be running it active on one of these other options. I might just be missing something, because they don't have the option there for no reason at all. What is just use for a standby physical NIC on a vSwitch?

[mark49808 · Accepted solution]

A good use case i have found is if you want to have redundancy, but dedicate nics for certain traffic. For example

NIC1: Active Vmotion. Standby VSAN

NIC2: Standby Vmotion: Active VSAN

This way you have dedicated NICs for each service, but if one fails, you fail over to sharing the same NIC for two different services. This lets you reduce the amount of ports needed, while still segmenting traffic (except in the rare case you have a NIC/port/switch issue).

[samcatoe]

Ok I see, so in this case, it would still be an active NIC on a different port group or VMK, but it will be a standby for a different service?

[mark49808]

yes, exactly. i do this in one environment to guarantee 10gbs to one port group, but also provide redundancy in case of a problem.