"Receive Packets Dropped" for multiple VMs when migrated to hosts running version 8.0.2

Products

• VMware vSphere ESXi

Issue/Introduction

• VC or vROps may report small packet drops for a DVS port statistics even there is no packet drops.
• In vsish, we do not see dropped packets under vmxnet3 stats and no increment in the counter "droppedRx" under the overall port stats.
• If the same virtual machine is moved to ESXi version 7.0, the VMs do not show packet drops.
• Fluctuations in pktsOutDropped and pktsInDropped are observed, this counter can increase to non-zero value and then back to 0.

Environment

VMware ESXi 8.0.2

Cause

As packets tranverse through vNIC backend, network stack including vswitch module, there can be drops in any of the network modules. The packet drops are calculated by merging all drops from all the network modules. However as some of modules does not track the drops directly, the drops are calculated by serveral counters which can not be read atomically. This can lead to false postive drops (means not really the packet drops)

Resolution

• With recent change in latest release 8.0.3P08 and 9.0.2, the drop counters reported to VC or vRops will never decrease or be negative. It may show some small drop counters initailly, but in a long run, the drop counter will not increase if there is no real drops.
• For customer which monitor these counters, should ignore the initail reported small drops due to the way of how this counters are calculated.
• There will be no immediate fix for this issue. We will try to redesign the way the drops should be countered in the future release.