NIC DRSS disabled for IvS

Products

• VMware NSX

Issue/Introduction

Industrial vSwitch (IvS) is used for manifacturing use case where realtime application is required. IvS can support low latency forwarding for industrial ethernet called Profinet. To achieve the low latency forwarding, IvS requires disabling DRSS on NICs. DRSS means Default Queue Receive Side Scaling and it allows multiple hardware queues for incoming packets. This configuration should be done through deployment steps. This KB article describes how to verify that DRSS is disabled on Mellanox NIC.

Environment

4.2.x

 

Resolution

If you use a Mellanox NIC, you can run the following command to confirm that DRSS is disabled for the NIC. 

- SSH to a ESXi host where IvS is enabled
- Run the esxcli command below with nmlx5_core

[root@localhost:~] esxcli system module parameters list -m nmlx5_core|grep DRSS
DRSS int 0,0 Number of HW queues for DEFQ RSS

 The output value should be 0,0 or just 0 if the DRSS is disabled correctly. (The number of "0" depends on the number of nics of that type on the host.)