Route Based on Physical NIC Load: VM Migration Supressed Due to Uplink Saturation

Products

• VMware vSphere ESX 8.x

Issue/Introduction

Symptoms:

• The virtual Machines are connected to a vSphere Distributed Switch(VDS) using the load balancing algorithms "Route Based on Physical NIC Load".
• The host has multiple uplinks(e.g., 2 uplinks), and both uplinks are currently with utilization exceeds 75%.
• In this state, virtual machines are not moving back and forth between the uplinks.

Environment

VMware vSphere ESXi 8.0

Cause

With "Route Based on Physical NIC Load" load balancing algorithms, the vSphere Distributed Switch only move a part of the virtual machine traffic to a new physical adapter that has free capacity,i.e., destination physical adapter is not saturated, this is one prerequisite.

Resolution

It is expected behavior.

Additional Information

Please refer to document below

https://techdocs.broadcom.com/us/en/vmware-cis/vsphere/vsphere/8-0/vsphere-networking-8-0/networking-policies/teaming-and-failover-policy/configure-nic-teaming-and-load-balancing-on-a-distributed-port-group-or-port.html