Monthly Archives: February 2012

VMWare ESXi slow network speed on guests

I recently tried building a few Linux VMs on a VMWare ESXi 5.0 host. All the virtual machines experienced very low network speed (<2Mbit/s) without any apparent reason. After some digging I found the solution on http://docwiki.cisco.com/wiki/Disable_LRO: Log into the ESXi host or its vCenter with vSphere Client. Select the host > Configuration > Software:Advanced Settings.
Select Net and scroll down slightly more than half way.
Set the following parameters from 1 to 0:

Net.VmxnetSwLROSL
Net.Vmxnet3SwLRO
Net.Vmxnet3HwLRO
Net.Vmxnet2SwLRO
Net.Vmxnet2HwLRO


Reboot the ESXi host to activate these changes.

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