2 Concurrent vMotions saturate a 10GB link with 4.1?

[AaronDelp01]

Hello all - I've been doing some thinking (and writing for an upcoming blog article) based on a peer's testing in our lab and I'm wondering if anybody can verify what we are seeing.

With the introduction of vSphere 4.1 the number of concurrent vMotions on 10GB has been increased to 8. Furthermore, the amount of bandwidth a vMotion can consume has been increased to 8Gbps. With no Traffic Shaping, NetIOC, or QoS, this sounds like it could lead to some pretty significant performance problems because the second (and subsequent) vMotions will saturate the link. Somebody suggested that the 8Gbps is the TOTAL bandwidth that the 8 vMotions would consume but that doesn't appear to be the case.

We did testing in our lab and we are seeing exactly the opposite. The first vMotion will spike to aruond 8 Gbps and the 2nd vMotion will peg the link at a little over 9 Gbps. Again, this is with no traffic shaping, QoS, NetIOC, etc.

Has anyone else seen this? If this is true it pretty much means that some form of Inbound and Outbound Traffic shaping MUST be utilized or you can get yourself in trouble pretty quick with a single pair of 10GB links.

Thank you for your time!

Aaron Delp

http://blog.aarondelp.com

http://blog.scottlowe.org/author/adelp/

[PduPreez]

Haha, the last comment in the video is hilarious :^O

I got this vivid image in my head that in future when you do a VMware POC on particular VMotion, you need to hand out some of those vomiting bags (those you get on airplanes) to the Companies IT people involved including the CIO watching, before you do a vMotion. Click to hurl in 1second