frankdenneman Frank Denneman is the Chief Technologist for AI at VMware by Broadcom. He is an author of the vSphere host and clustering deep dive series, as well as a podcast host for the Unexplored Territory podcast. You can follow him on Twitter @frankdenneman

vMotion over layer 3?

18 sec read

This question regularly pops up on twitter and the community forums. And yes it works but VMware does not support vMotion interfaces in different subnets.
The reason is that this can break functionality in higher-level features that rely on vMotion to work.
If you think Routed vMotion (vMotion interfaces in different subnets) is something that should be available in the modern datacenter, please fill out a feature request. The more feature requests we receive; the more priority can be applied to the development process of the feature.

frankdenneman Frank Denneman is the Chief Technologist for AI at VMware by Broadcom. He is an author of the vSphere host and clustering deep dive series, as well as a podcast host for the Unexplored Territory podcast. You can follow him on Twitter @frankdenneman

Help Us Make vMotion Even Better

The vMotion product team is looking for input on how to improve vMotion.  vMotion has proven to be a paradigm shift of datacenter management....
frankdenneman
21 sec read

Disable vMotion for a single VM

This question pops up regularly on the VMTN forums and reddit. It’s a viable question but the admins who request this feature usually don’t...
frankdenneman
1 min read

vSphere 5.1 update 1 release fixes Storage vMotion rename…

vSphere 5.1 update 1 is released today which contains several updates and bug fixes for both ESXi and vCenter Server 5.1. This release contains...
frankdenneman
29 sec read

2 Replies to “vMotion over layer 3?”

  1. Hey mate, Assuming the pre-requisities for vMotion are met – at least 5ms latency response time or better (I thought I read somewhere this has been bumped up to 10ms?) then will this work (unsupported or not) in any scenario with different subnets? What scenarios/topologies could you see it not working? Also do you think routed vMotion has a limit of the number of hops it can handle also or does it also come back to latency/response time?

    1. Andre, yes, the 10ms “Metro vMotion” capability is possible with Enterprise+ licensing.
      I agree – I don’t think the complexity has much to do with *technically* supporting L3 vs. L2 for vMotion so much as the options L3 gives for people to attempt vMotion over all kinds of “weird” infrastructure. For example, the current L2 restriction tends to discourage people from attempting to configure vMotion over a low-bandwidth WAN links since they don’t typically try to span L2 networks over those same links. It’s one of those “it depennds” things: the bandwidth and latency need to support transferring X MB data between locations faster than those X MB are being changed on the source machine. If not, the target will never catch up — or will need to be suspended/throttled too much to be practical.
      For L3 vMotion, I think a lot of people would give that a go just because it is now ‘supported.’ The support matrix just became exponentially more complex, and the number of support calls would likely increase the same way.
      Beyond the bandwidth+latency issues, we have to look at security: that traffic is in-memory host data and not protected by the vSphere layer. Encryption would have to come into play if that traffic were to leave the datacenter — at least IMHO.

Comments are closed.