Need some clarification on NIC speed requirement to vMotion

[pbalderos]

Hello All,

I was trying to vMotion one of our VMs and received an error that basically said the vSwitch needs to be a 1000GBs. I am not understanding why my Network adapter says it's has a gigabit connection but the section that shows "actual speed" is only 100mb. Any thoughts on this?

[jhague]

Is the physical switch port also set to auto negotiate like the network adapter? I.e it's not forcing the speed down to 100/Full Duplex?

[pbalderos]

hi jhague

i am not sure, I will ask our network engineer to check when I get into the office today and follow up on the thread. So you are saying the

it could be that the switch is set to throttle the traffic down?

[a_p_ · Accepted solution]

This could be related either the physical switch port configuration - as mentioned by jhague‌ - or also a bad network cable.

André

[jhague]

Hi - yes from the screenshot we can see the NIC is 1Gbps capable and the speed from the server side is set to 'auto negotiate' so I'm wondering if the speed has been fixed on the port. It used to be common practice to hard set the speed as auto negotiation was erratic but with 1Gbps+ cards it's generally recommended to let them negotiate the speed automatically.

[pbalderos]

It ended up being a network cable. So I wonder if that bad cable degraded the speed down to 100Mbps or if it is the behavior of the vSwitch to default to 100Mbps when there is an issue?

[a_p_]

That's actually a physical issue. If the network cable doesn't meet the requirements (e.g. Cat5), auto-negotiation will try to reduce the speed to allow a connection, unless the cable is bad at all.

André

[pbalderos]

Thank you! That information was very helpful and I will make note of it in the future.