ESXi RX Buffer Change Failure with "Unable to complete Sysinfo operation" and "Unsupported RX ring size" Observed in vmkernel Logs

Products

• VMware vSphere ESXi 8.0

Issue/Introduction

When attempting to modify the Receive (RX) Buffer size for an ESXi host uplink via the Command Line Interface (CLI), the operation fails with the following error message:

Unable to complete sysinfo operation. Please see the VMkernel log files for more details: Not supported.

/var/log/vmkernel.log show following entries:

2026-03-17T11:53:47.538Z cpu32:2097388)WARNING: bnxtnet: bnxtnet_ring_params_set:3925: [vmnic2 : 0x43120864c3d0] Unsupported RX ring size (8192)
2026-03-17T11:53:57.322Z cpu32:2097388)WARNING: bnxtnet: bnxtnet_ring_params_set:3925: [vmnic3 : 0x431208660d10] Unsupported RX ring size (8192)

Environment

VMware vSphere ESXi 8.x

Cause

This error occurs because the requested RX buffer value exceeds the maximum hardware limit supported by the physical network adapter or its driver. ESXi cannot apply a configuration that the underlying hardware is incapable of handling.

Resolution

To resolve this, you must identify the hardware's maximum supported ring buffer limits and ensure your desired value falls within that range.

1. Identify Supported Buffer Limits

Run the following command to see the current and maximum allowable values for a specific uplink (replace vmnicX with your actual device name, e.g., vmnic0):

esxcli network nic ring current get -n vmnicX

2. Verify the "Maximum" Column

The output will display the Maximum allowable RX and TX values.

Example:

   Current Ring Size:
   RingInfo:
      RX: 1023
      RX Mini: 0
      RX Jumbo: 0
      TX: 1023

  Preset Maximum Ring Size:
  RingInfo:
      Max RX: 4095
      Max RX Mini: 0
      Max RX Jumbo: 0
      Max TX: 4095

Current RX: The value currently in use.

Maximum RX: The highest value the hardware supports.

3. Set a Valid Value

Ensure the value you are attempting to set is less than or equal to the "Maximum RX" value identified in the previous step. To apply the change, use:

esxcli network nic ring current set -r [Value] -n vmnicX

Additional Information

net-Interface-Driver