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I have a question about VMware and NIC Teaming. Here is my easy test scenario. I have two VMs. VM1 and VM2. I want to copy 1 big file from VM1 to VM2 because I want to see that I can gain more copy speed than 1Gbit/s. But i can’t get more speed than about 113MB/s… (which is nearly the 1Gbit/s) But I don’t understand why I can’t get more with my configuration.

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For the explanation of my environment I drew a little picture… I thought this would be easier to understand my starting situation: enter image description here

So as you can see I have configured a NIC Teaming with 4x 1Gbit/s so i think that in theory I could gain up to 4Gbit/s speed between two VMs on two different but similar configured ESXi servers. That I will nerver reach the 4Gbit/s in practis is clear for me, but I should be able to reach at least a Value of more than 200MB/s…

The utilization of my vSwitch1 (With the Virtual Machine Port Group named “NIC”) isn’t really not high. So where is the Problem?

Thank you for your Thoughts and your help! Maybe i just made a configuration misstake or have a missunderstanding about the NIC Teaming...

EDIT: If it matters: VM1 is a Windows 8.1 VM / VM2 is a Windows Server 2012R2

ewwhite
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frupfrup
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2 Answers2

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A NIC team does NOT provide any more bandwidth. A single network connection (like the one between your 2 VM's) will never use more than one of the possible NIC's in the team. The point of a NIC team is to balance many connections across the available NIC's.

With your chosen load balancing method (Route based on the originating virtual switch port ID) each VM will always use the same single physical NIC. From http://www.vmware.com/files/pdf/virtual_networking_concepts.pdf

Route based on the originating virtual switch port ID — Choose an uplink based on the virtual port where the traffic entered the virtual switch. This is the default configuration and the one most commonly deployed. When you use this setting, traffic from a given virtual Ethernet adapter is consistently sent to the same physical adapter unless there is a failover to another adapter in the NIC team.

In this case even breaking up your file transfer into multiple, smaller ones will not speed anything up, as you are still limited to the same, single NIC.

D34DM347
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While NIC Teaming can provide additional bandwidth, it's greatest benefit is fault tolerance to your setup. There is still an aggregate bandwidth increase, but as far as I know with most equipment, you will not be able to get greater than 1gbps for a single transfer even if you have 4 teamed 1gbps connections. While you couldn't get more than 1gbps for a single file, you would be able to get up to 1gbps for four file transfers simultaneously (in a sinle direction).

To get more than 1gbps in your transfers you'd need to break up your files or getting a higher bandwidth media (such as 10gbps).

TheGrandPackard
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