spped and duplex within VM

[Wimo]

A lot of threads on this general topic at the host level, couldn't find an answer to this though (maybe I didn't look hard enough).

The hosts in some of our clusters have gig connections for the vswitch NICs, and some are 100 Full.

In each case, how should the NIC inside the Windows VM be set? On the Advanced tab of the "VMware Accelerated AMD PCNet Adapter Properties" are choices for "External PHY" and "Full Duplex."

The PHY one I guess should be Auto for Gig and 100Full for 100Full - yes?

And the duplex one defaults to "Use adapter setting." Is this what it should be in both cases? The other choices are AUI-Full Duplex, UTP-Full Duplex, and Off.

[oreeh · Accepted solution]

I don't think that the speed and duplex settings inside a VM really do anything useful.

The speed depends on the virtual NIC used and since all the NICs (and Switches) are virtual anyway and in fact only a memory copy takes place...

[RDPetruska]

The labels inside the guest are just that - labels. ALL network traffic is performed by the host CPU, and is not throttled (unless you specify a certain max. percentage, I believe).

[kharbin]

The VM is abstracted from the physical hardware and its settings. There is nothing you need to set or change inside the VM. The VMs vNIC will assume the phyical properties of the physical NIC through which it is communicating.

Changes to speed and duplex are done at the host level, and these changes are inherited by the virtual machines.

my 2 cents

Ken Harbin

www.esXpress.com

[Wimo]

Thanks guys. You all said about the same thing, so to the swiftest go the spoils (Correct points).