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Enabling the config option vmxnet3FlapThrottleRate in a virtual machine (2148348)

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This article provides steps to enable the config option vmxnet3FlapThrottleRate to throttle the number of port enable/disable events from vmxnet3 backend.


When vmxnet3FlapThrottleRate option is set, it represents the number of vmxnet3 enable/disable commands allowed by the backend in 1 second. If the virtual machine sends more than the vmxnet3FlapThrottleRate commands in 1 second, the backend disables the device and subsequent commands in the same 1 second window result in a no-op (that is they are ignored). If the rate of virtual machine commands drops to less than vmxnet3FlapThrottleRate per second, the backend resumes servicing the commands.

The ISM should be disabled for provisioning the VMs.

Note: This config option is not enabled by default and we need to explicitly set it to 1 to throttle the rate of disable/enable events and this is a throttling workaround from vmxnet3 side.

To enable the config option:
  1. Log in through SSH as root on the ESXi host.
  2. In the host, open the /etc/vmware/config file using a test editor.
  3. Add this entry in the file:

     vmxnet3FlapThrottleRate = "1".

  4. Save and close the file.
  5. Power cycle all virtual machines.

    Note: After the virtual machines are powered on, from the vmware.log, verify if this config option is being read accordingly.

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