Having successfully followed VMware KB article setting up multi-nic vMotion, I am now struggling to get this working with a two core switches.

A single Active vmnic and a single Standby vmnic is functioning as it should.

However, the issue is due to the nature of the setup. We have 2 core switches (sets of stacked switches), in a active/passive setup connected via LACP.

How can i get this working with 2 core switches?

Working Setup

The working configuration has 1 active and 1 standby vmnics from a single Core.

Vmnic 3 & 12 are from Core 1. A second vmkernal is also setup to the opposite active an standby adapters.

vMotion - Multi-nic

Not Working

Vmnic 7 & 8 are from Core 2. Once again, a second vmkernal is setup to reflect the opposite of active and standby adapters.

vMotion - Multi-nic Dual Core

If anyone can shed some light on this or have a plausible solution, I am in the position to test this before putting into live.

  • I've been here too - and I am beginning to wonder whether having two sets of stacked switches for use with VMware is a good idea (or at all). I've seen very little extra value from having this extra level of redundancy but it has been an extra complexity challenging every networking project. If I were doing all this again, I'd just stack all my switches into one. The failure of a whole stack seems well within our SLAs and we can get redundant hardware and extra throughput within a single stack.
    – dunxd
    Apr 22, 2013 at 16:53
  • @dunxd Indeed, having two core stacks has increased level of configuration and complication with little additional benefits. Unfortunately, you can't always change backbone infrastructure and have to make do with what you have.
    – Cold T
    Apr 23, 2013 at 8:56
  • Oh yes - it is a lesson learnt but not a lesson easy to put into practice. Still stuck with the two cores - next hardware refresh will be the first opportunity to make a change.
    – dunxd
    Apr 23, 2013 at 13:46

1 Answer 1


Have found a working solution with two core stacks and using vSwitches (rather then vDS).

In one simple sentence, the key idea is to ensure you only have 1 active vmnic per port group with everything else as standby.

So therefore, for every vmnic you must have a single port group. In my case, I have two nics per core stack. Only two will ever be utilised.



Ensure you have the IPs assigned from the same IP subnet.

Performance tab under vSphere Client easily shows both nics are being utilised.

Ultimately, this avoids any LACP/ etherchannels needing to be setup. As recommended, Jumbo frames should also be enabled for vMotion VMNics.

REF: Designing your vMotion network

Thanks goes to @Dan for pointing out the reference and pointing me toward the right direction.

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